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Ranger v.1.1.1
==============

Ranger is a free console file manager that gives you greater flexibility
and a good overview of your files without having to leave your *nix console.
It visualizes the directory tree in two dimensions: the directory hierarchy
on one, lists of files on the other, with a preview to the right so you know
where you'll be going.

The default keys are similar to those of Vim, Emacs and Midnight Commander,
though Ranger is easily controllable with just the arrow keys or the mouse.

The program is written in Python (2.6 or 3.1) and uses curses for the
text-based user interface.


About
-----

* Author:          Roman Zimbelmann  <romanz@lavabit.com>
* Website:         http://savannah.nongnu.org/projects/ranger
* License:         GNU General Public License Version 3

* Download URL of the newest stable version:
http://git.savannah.gnu.org/cgit/ranger.git/snapshot/ranger-stable.tar.gz

* Git Clone URL:
git clone http://git.sv.gnu.org/r/ranger.git


Design Goals
------------

* An easily maintainable file manager in a high level language
* A quick way to switch directories and browse the file system
* Keep it small but useful, do one thing and do it well
* Console based, with smooth integration into the unix shell


Features
--------

* Multi-column display (Miller Columns)
* Preview of the selected file/directory
* Common file operations (create/chmod/copy/delete/...)
* VIM-like console and hotkeys
* Automatically determine file types and run them with correct programs
* Change the directory of your shell after exiting ranger
* Tabs, Bookmarks, Mouse support


Dependencies
------------

* A *nix-like operating system
* Python 2.6 or Python 3.1 with the curses module

Optional:
* The "file" program
* A pager ("less" by default)


Getting Started
---------------

Ranger can be started without installing.  Just run the executable (in
a terminal.)  The switch "--clean" will prevent it from creating or
accessing configuration files.

Follow the instructions in the INSTALL file for installing ranger.

After starting ranger, you should see 4 columns. The third one is the main
column, the directory where you're currently at.  To the left you see the
parent directories and to the right there's a preview of the object you're
pointing at.  Now use the Arrow Keys to navigate, Enter to open a file
or type Q to quit.

To customize ranger, copy the files from ranger/defaults/ to ~/.ranger/
and modify them according to your wishes.


Troubleshooting, Getting Help
-----------------------------

If you encounter an error, try running ranger with --debug.  This will
sometimes display more detailed information about the error.  Also, try
deactivating optimization:

PYTHONOPTIMIZE="" ranger --debug

Report bugs on savannah:  (please include as much information as possible)
http://savannah.nongnu.org/bugs/?func=additem&group=ranger

Ask questions on the mailing list:
http://lists.nongnu.org/mailman/listinfo/ranger-users


Further Reading
---------------

Check the man page for information on common features and hotkeys.

The most detailed manual is accessible by pressing "?" from inside ranger.
It is also available at ranger/help/, contained in the *.py files.

The file ranger/defaults/keys.py contains all key combinations, so that's
another place you may want to check out.
ef='#n1256'>1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178
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<pre id='vimCodeElement'>
<span id="L1" class="LineNr">   1 </span><span class="SalientComment">## undo/redo</span>
<span id="L2" class="LineNr">   2 </span>
<span id="L3" class="LineNr">   3 </span><span class="Comment"># for every undoable event, create a type of *operation* that contains all the</span>
<span id="L4" class="LineNr">   4 </span><span class="Comment"># information needed to reverse it</span>
<span id="L5" class="LineNr">   5 </span><span class="muData">exclusive-container</span> <a href='012-editor-undo.mu.html#L5'>operation</a> [
<span id="L6" class="LineNr">   6 </span>  typing:<a href='012-editor-undo.mu.html#L11'>insert-operation</a>
<span id="L7" class="LineNr">   7 </span>  move:<a href='012-editor-undo.mu.html#L26'>move-operation</a>
<span id="L8" class="LineNr">   8 </span>  delete:<a href='012-editor-undo.mu.html#L43'>delete-operation</a>
<span id="L9" class="LineNr">   9 </span>]
<span id="L10" class="LineNr">  10 </span>
<span id="L11" class="LineNr">  11 </span><span class="muData">container</span> <a href='012-editor-undo.mu.html#L11'>insert-operation</a> [
<span id="L12" class="LineNr">  12 </span>  before-row:num
<span id="L13" class="LineNr">  13 </span>  before-column:num
<span id="L14" class="LineNr">  14 </span>  before-top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char
<span id="L15" class="LineNr">  15 </span>  after-row:num
<span id="L16" class="LineNr">  16 </span>  after-column:num
<span id="L17" class="LineNr">  17 </span>  after-top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char
<span id="L18" class="LineNr">  18 </span>  <span class="Comment"># inserted text is from 'insert-from' until 'insert-until'; list doesn't have to terminate</span>
<span id="L19" class="LineNr">  19 </span>  insert-from:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char
<span id="L20" class="LineNr">  20 </span>  insert-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char
<span id="L21" class="LineNr">  21 </span>  tag:num  <span class="Comment"># event causing this operation; might be used to coalesce runs of similar events</span>
<span id="L22" class="LineNr">  22 </span>  <span class="Conceal">¦</span> <span class="Comment"># 0: no coalesce (enter+indent)</span>
<span id="L23" class="LineNr">  23 </span>  <span class="Conceal">¦</span> <span class="Comment"># 1: regular alphanumeric characters</span>
<span id="L24" class="LineNr">  24 </span>]
<span id="L25" class="LineNr">  25 </span>
<span id="L26" class="LineNr">  26 </span><span class="muData">container</span> <a href='012-editor-undo.mu.html#L26'>move-operation</a> [
<span id="L27" class="LineNr">  27 </span>  before-row:num
<span id="L28" class="LineNr">  28 </span>  before-column:num
<span id="L29" class="LineNr">  29 </span>  before-top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char
<span id="L30" class="LineNr">  30 </span>  after-row:num
<span id="L31" class="LineNr">  31 </span>  after-column:num
<span id="L32" class="LineNr">  32 </span>  after-top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char
<span id="L33" class="LineNr">  33 </span>  tag:num  <span class="Comment"># event causing this operation; might be used to coalesce runs of similar events</span>
<span id="L34" class="LineNr">  34 </span>  <span class="Conceal">¦</span> <span class="Comment"># 0: no coalesce (touch events, etc)</span>
<span id="L35" class="LineNr">  35 </span>  <span class="Conceal">¦</span> <span class="Comment"># 1: left arrow</span>
<span id="L36" class="LineNr">  36 </span>  <span class="Conceal">¦</span> <span class="Comment"># 2: right arrow</span>
<span id="L37" class="LineNr">  37 </span>  <span class="Conceal">¦</span> <span class="Comment"># 3: up arrow</span>
<span id="L38" class="LineNr">  38 </span>  <span class="Conceal">¦</span> <span class="Comment"># 4: down arrow</span>
<span id="L39" class="LineNr">  39 </span>  <span class="Conceal">¦</span> <span class="Comment"># 5: line up</span>
<span id="L40" class="LineNr">  40 </span>  <span class="Conceal">¦</span> <span class="Comment"># 6: line down</span>
<span id="L41" class="LineNr">  41 </span>]
<span id="L42" class="LineNr">  42 </span>
<span id="L43" class="LineNr">  43 </span><span class="muData">container</span> <a href='012-editor-undo.mu.html#L43'>delete-operation</a> [
<span id="L44" class="LineNr">  44 </span>  before-row:num
<span id="L45" class="LineNr">  45 </span>  before-column:num
<span id="L46" class="LineNr">  46 </span>  before-top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char
<span id="L47" class="LineNr">  47 </span>  after-row:num
<span id="L48" class="LineNr">  48 </span>  after-column:num
<span id="L49" class="LineNr">  49 </span>  after-top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char
<span id="L50" class="LineNr">  50 </span>  deleted-text:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char
<span id="L51" class="LineNr">  51 </span>  delete-from:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char
<span id="L52" class="LineNr">  52 </span>  delete-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char
<span id="L53" class="LineNr">  53 </span>  tag:num  <span class="Comment"># event causing this operation; might be used to coalesce runs of similar events</span>
<span id="L54" class="LineNr">  54 </span>  <span class="Conceal">¦</span> <span class="Comment"># 0: no coalesce (ctrl-k, ctrl-u)</span>
<span id="L55" class="LineNr">  55 </span>  <span class="Conceal">¦</span> <span class="Comment"># 1: backspace</span>
<span id="L56" class="LineNr">  56 </span>  <span class="Conceal">¦</span> <span class="Comment"># 2: delete</span>
<span id="L57" class="LineNr">  57 </span>]
<span id="L58" class="LineNr">  58 </span>
<span id="L59" class="LineNr">  59 </span><span class="Comment"># every editor accumulates a list of operations to undo/redo</span>
<span id="L60" class="LineNr">  60 </span><span class="muData">container</span> editor [
<span id="L61" class="LineNr">  61 </span>  undo:&amp;:<a href='../064list.mu.html#L6'>list</a>:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a>
<span id="L62" class="LineNr">  62 </span>  redo:&amp;:<a href='../064list.mu.html#L6'>list</a>:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a>
<span id="L63" class="LineNr">  63 </span>]
<span id="L64" class="LineNr">  64 </span>
<span id="L65" class="LineNr">  65 </span><span class="Comment"># ctrl-z - undo operation</span>
<span id="L66" class="LineNr">  66 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L67" class="LineNr">  67 </span>  <span class="Delimiter">{</span>
<span id="L68" class="LineNr">  68 </span>  <span class="Conceal">¦</span> undo?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">26/ctrl-z</span>
<span id="L69" class="LineNr">  69 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> undo?
<span id="L70" class="LineNr">  70 </span>  <span class="Conceal">¦</span> undo:&amp;:<a href='../064list.mu.html#L6'>list</a>:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
<span id="L71" class="LineNr">  71 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> undo
<span id="L72" class="LineNr">  72 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first undo
<span id="L73" class="LineNr">  73 </span>  <span class="Conceal">¦</span> undo <span class="Special">&lt;-</span> <a href='../064list.mu.html#L24'>rest</a> undo
<span id="L74" class="LineNr">  74 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">undo:offset</span>, undo
<span id="L75" class="LineNr">  75 </span>  <span class="Conceal">¦</span> redo:&amp;:<a href='../064list.mu.html#L6'>list</a>:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">redo:offset</span>
<span id="L76" class="LineNr">  76 </span>  <span class="Conceal">¦</span> redo <span class="Special">&lt;-</span> push op, redo
<span id="L77" class="LineNr">  77 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">redo:offset</span>, redo
<span id="L78" class="LineNr">  78 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='012-editor-undo.mu.html#L78'>&lt;handle-undo&gt;</a></span>
<span id="L79" class="LineNr">  79 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">1/go-render</span>
<span id="L80" class="LineNr">  80 </span>  <span class="Delimiter">}</span>
<span id="L81" class="LineNr">  81 </span>]
<span id="L82" class="LineNr">  82 </span>
<span id="L83" class="LineNr">  83 </span><span class="Comment"># ctrl-y - redo operation</span>
<span id="L84" class="LineNr">  84 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L85" class="LineNr">  85 </span>  <span class="Delimiter">{</span>
<span id="L86" class="LineNr">  86 </span>  <span class="Conceal">¦</span> redo?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">25/ctrl-y</span>
<span id="L87" class="LineNr">  87 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> redo?
<span id="L88" class="LineNr">  88 </span>  <span class="Conceal">¦</span> redo:&amp;:<a href='../064list.mu.html#L6'>list</a>:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">redo:offset</span>
<span id="L89" class="LineNr">  89 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> redo
<span id="L90" class="LineNr">  90 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first redo
<span id="L91" class="LineNr">  91 </span>  <span class="Conceal">¦</span> redo <span class="Special">&lt;-</span> <a href='../064list.mu.html#L24'>rest</a> redo
<span id="L92" class="LineNr">  92 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">redo:offset</span>, redo
<span id="L93" class="LineNr">  93 </span>  <span class="Conceal">¦</span> undo:&amp;:<a href='../064list.mu.html#L6'>list</a>:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
<span id="L94" class="LineNr">  94 </span>  <span class="Conceal">¦</span> undo <span class="Special">&lt;-</span> push op, undo
<span id="L95" class="LineNr">  95 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">undo:offset</span>, undo
<span id="L96" class="LineNr">  96 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='012-editor-undo.mu.html#L96'>&lt;handle-redo&gt;</a></span>
<span id="L97" class="LineNr">  97 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">1/go-render</span>
<span id="L98" class="LineNr">  98 </span>  <span class="Delimiter">}</span>
<span id="L99" class="LineNr">  99 </span>]
<span id="L100" class="LineNr"> 100 </span>
<span id="L101" class="LineNr"> 101 </span><span class="Comment"># undo typing</span>
<span id="L102" class="LineNr"> 102 </span>
<span id="L103" class="LineNr"> 103 </span><span class="muScenario">scenario</span> editor-can-undo-typing [
<span id="L104" class="LineNr"> 104 </span>  <span class="Constant">local-scope</span>
<span id="L105" class="LineNr"> 105 </span>  <span class="Comment"># create an editor and type a character</span>
<span id="L106" class="LineNr"> 106 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L107" class="LineNr"> 107 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L108" class="LineNr"> 108 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L109" class="LineNr"> 109 </span>  assume-console [
<span id="L110" class="LineNr"> 110 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
<span id="L111" class="LineNr"> 111 </span>  ]
<span id="L112" class="LineNr"> 112 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L113" class="LineNr"> 113 </span>  <span class="Comment"># undo</span>
<span id="L114" class="LineNr"> 114 </span>  assume-console [
<span id="L115" class="LineNr"> 115 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L116" class="LineNr"> 116 </span>  ]
<span id="L117" class="LineNr"> 117 </span>  run [
<span id="L118" class="LineNr"> 118 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L119" class="LineNr"> 119 </span>  ]
<span id="L120" class="LineNr"> 120 </span>  <span class="Comment"># character should be gone</span>
<span id="L121" class="LineNr"> 121 </span>  screen-should-contain [
<span id="L122" class="LineNr"> 122 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L123" class="LineNr"> 123 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L124" class="LineNr"> 124 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L125" class="LineNr"> 125 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L126" class="LineNr"> 126 </span>  ]
<span id="L127" class="LineNr"> 127 </span>  <span class="Comment"># cursor should be in the right place</span>
<span id="L128" class="LineNr"> 128 </span>  assume-console [
<span id="L129" class="LineNr"> 129 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
<span id="L130" class="LineNr"> 130 </span>  ]
<span id="L131" class="LineNr"> 131 </span>  run [
<span id="L132" class="LineNr"> 132 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L133" class="LineNr"> 133 </span>  ]
<span id="L134" class="LineNr"> 134 </span>  screen-should-contain [
<span id="L135" class="LineNr"> 135 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L136" class="LineNr"> 136 </span>  <span class="Conceal">¦</span><span class="Constant"> .1         .</span>
<span id="L137" class="LineNr"> 137 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L138" class="LineNr"> 138 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L139" class="LineNr"> 139 </span>  ]
<span id="L140" class="LineNr"> 140 </span>]
<span id="L141" class="LineNr"> 141 </span>
<span id="L142" class="LineNr"> 142 </span><span class="Comment"># save operation to undo</span>
<span id="L143" class="LineNr"> 143 </span><span class="muRecipe">after</span> <span class="Constant">&lt;begin-insert-character&gt;</span> [
<span id="L144" class="LineNr"> 144 </span>  top-before:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L145" class="LineNr"> 145 </span>  cursor-before:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L146" class="LineNr"> 146 </span>]
<span id="L147" class="LineNr"> 147 </span><span class="muRecipe">before</span> <span class="Constant">&lt;end-insert-character&gt;</span> [
<span id="L148" class="LineNr"> 148 </span>  top-after:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L149" class="LineNr"> 149 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L150" class="LineNr"> 150 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L151" class="LineNr"> 151 </span>  undo:&amp;:<a href='../064list.mu.html#L6'>list</a>:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
<span id="L152" class="LineNr"> 152 </span>  <span class="Delimiter">{</span>
<span id="L153" class="LineNr"> 153 </span>  <span class="Conceal">¦</span> <span class="Comment"># if previous operation was an insert, coalesce this operation with it</span>
<span id="L154" class="LineNr"> 154 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> undo
<span id="L155" class="LineNr"> 155 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first undo
<span id="L156" class="LineNr"> 156 </span>  <span class="Conceal">¦</span> typing:<a href='012-editor-undo.mu.html#L11'>insert-operation</a>, is-insert?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">typing:variant</span>
<span id="L157" class="LineNr"> 157 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-insert?
<span id="L158" class="LineNr"> 158 </span>  <span class="Conceal">¦</span> previous-coalesce-tag:num <span class="Special">&lt;-</span> get typing, <span class="Constant">tag:offset</span>
<span id="L159" class="LineNr"> 159 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> previous-coalesce-tag
<span id="L160" class="LineNr"> 160 </span>  <span class="Conceal">¦</span> before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L161" class="LineNr"> 161 </span>  <span class="Conceal">¦</span> insert-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
<span id="L162" class="LineNr"> 162 </span>  <span class="Conceal">¦</span> typing <span class="Special">&lt;-</span> put typing, <span class="Constant">insert-until:offset</span>, insert-until
<span id="L163" class="LineNr"> 163 </span>  <span class="Conceal">¦</span> typing <span class="Special">&lt;-</span> put typing, <span class="Constant">after-row:offset</span>, cursor-row
<span id="L164" class="LineNr"> 164 </span>  <span class="Conceal">¦</span> typing <span class="Special">&lt;-</span> put typing, <span class="Constant">after-column:offset</span>, cursor-column
<span id="L165" class="LineNr"> 165 </span>  <span class="Conceal">¦</span> typing <span class="Special">&lt;-</span> put typing, <span class="Constant">after-top-of-screen:offset</span>, top-after
<span id="L166" class="LineNr"> 166 </span>  <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">0/insert-operation</span>, typing
<span id="L167" class="LineNr"> 167 </span>  <span class="Conceal">¦</span> <span class="muControl">break</span> <span class="Constant">+done-adding-insert-operation</span>
<span id="L168" class="LineNr"> 168 </span>  <span class="Delimiter">}</span>
<span id="L169" class="LineNr"> 169 </span>  <span class="Comment"># if not, create a new operation</span>
<span id="L170" class="LineNr"> 170 </span>  insert-from:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> cursor-before
<span id="L171" class="LineNr"> 171 </span>  insert-to:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> insert-from
<span id="L172" class="LineNr"> 172 </span>  op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
<span id="L173" class="LineNr"> 173 </span>  *op <span class="Special">&lt;-</span> merge <span class="Constant">0/insert-operation</span>, save-row/before, save-column/before, top-before, cursor-row/after, cursor-column/after, top-after, insert-from, insert-to, <span class="Constant">1/coalesce</span>
<span id="L174" class="LineNr"> 174 </span>  editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L202'>add-operation</a> editor, op
<span id="L175" class="LineNr"> 175 </span><span class="Constant">  +done-adding-insert-operation</span>
<span id="L176" class="LineNr"> 176 </span>]
<span id="L177" class="LineNr"> 177 </span>
<span id="L178" class="LineNr"> 178 </span><span class="Comment"># enter operations never coalesce with typing before or after</span>
<span id="L179" class="LineNr"> 179 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L861'>&lt;begin-insert-enter&gt;</a></span> [
<span id="L180" class="LineNr"> 180 </span>  cursor-row-before:num <span class="Special">&lt;-</span> copy cursor-row
<span id="L181" class="LineNr"> 181 </span>  cursor-column-before:num <span class="Special">&lt;-</span> copy cursor-column
<span id="L182" class="LineNr"> 182 </span>  top-before:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L183" class="LineNr"> 183 </span>  cursor-before:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L184" class="LineNr"> 184 </span>]
<span id="L185" class="LineNr"> 185 </span><span class="muRecipe">before</span> <span class="Constant"><a href='002-typing.mu.html#L863'>&lt;end-insert-enter&gt;</a></span> [
<span id="L186" class="LineNr"> 186 </span>  top-after:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L187" class="LineNr"> 187 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L188" class="LineNr"> 188 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L189" class="LineNr"> 189 </span>  <span class="Comment"># never coalesce</span>
<span id="L190" class="LineNr"> 190 </span>  insert-from:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> cursor-before
<span id="L191" class="LineNr"> 191 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L192" class="LineNr"> 192 </span>  insert-to:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
<span id="L193" class="LineNr"> 193 </span>  op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
<span id="L194" class="LineNr"> 194 </span>  *op <span class="Special">&lt;-</span> merge <span class="Constant">0/insert-operation</span>, cursor-row-before, cursor-column-before, top-before, cursor-row/after, cursor-column/after, top-after, insert-from, insert-to, <span class="Constant">0/never-coalesce</span>
<span id="L195" class="LineNr"> 195 </span>  editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L202'>add-operation</a> editor, op
<span id="L196" class="LineNr"> 196 </span>]
<span id="L197" class="LineNr"> 197 </span>
<span id="L198" class="LineNr"> 198 </span><span class="Comment"># Everytime you add a new operation to the undo stack, be sure to clear the</span>
<span id="L199" class="LineNr"> 199 </span><span class="Comment"># redo stack, because it's now obsolete.</span>
<span id="L200" class="LineNr"> 200 </span><span class="Comment"># Beware: since we're counting cursor moves as operations, this means just</span>
<span id="L201" class="LineNr"> 201 </span><span class="Comment"># moving the cursor can lose work on the undo stack.</span>
<span id="L202" class="LineNr"> 202 </span><span class="muRecipe">def</span> <a href='012-editor-undo.mu.html#L202'>add-operation</a> editor:&amp;:editor, op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a><span class="muRecipe"> -&gt; </span>editor:&amp;:editor [
<span id="L203" class="LineNr"> 203 </span>  <span class="Constant">local-scope</span>
<span id="L204" class="LineNr"> 204 </span>  <span class="Constant">load-ingredients</span>
<span id="L205" class="LineNr"> 205 </span>  undo:&amp;:<a href='../064list.mu.html#L6'>list</a>:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
<span id="L206" class="LineNr"> 206 </span>  undo <span class="Special">&lt;-</span> push op undo
<span id="L207" class="LineNr"> 207 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">undo:offset</span>, undo
<span id="L208" class="LineNr"> 208 </span>  redo:&amp;:<a href='../064list.mu.html#L6'>list</a>:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">redo:offset</span>
<span id="L209" class="LineNr"> 209 </span>  redo <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
<span id="L210" class="LineNr"> 210 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">redo:offset</span>, redo
<span id="L211" class="LineNr"> 211 </span>]
<span id="L212" class="LineNr"> 212 </span>
<span id="L213" class="LineNr"> 213 </span><span class="muRecipe">after</span> <span class="Constant"><a href='012-editor-undo.mu.html#L78'>&lt;handle-undo&gt;</a></span> [
<span id="L214" class="LineNr"> 214 </span>  <span class="Delimiter">{</span>
<span id="L215" class="LineNr"> 215 </span>  <span class="Conceal">¦</span> typing:<a href='012-editor-undo.mu.html#L11'>insert-operation</a>, is-insert?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">typing:variant</span>
<span id="L216" class="LineNr"> 216 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-insert?
<span id="L217" class="LineNr"> 217 </span>  <span class="Conceal">¦</span> start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get typing, <span class="Constant">insert-from:offset</span>
<span id="L218" class="LineNr"> 218 </span>  <span class="Conceal">¦</span> end:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get typing, <span class="Constant">insert-until:offset</span>
<span id="L219" class="LineNr"> 219 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
<span id="L220" class="LineNr"> 220 </span>  <span class="Conceal">¦</span> before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L32'>prev</a> start
<span id="L221" class="LineNr"> 221 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L222" class="LineNr"> 222 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L385'>remove-between</a> before-cursor, end
<span id="L223" class="LineNr"> 223 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> get typing, <span class="Constant">before-row:offset</span>
<span id="L224" class="LineNr"> 224 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L225" class="LineNr"> 225 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> get typing, <span class="Constant">before-column:offset</span>
<span id="L226" class="LineNr"> 226 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L227" class="LineNr"> 227 </span>  <span class="Conceal">¦</span> top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get typing, <span class="Constant">before-top-of-screen:offset</span>
<span id="L228" class="LineNr"> 228 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top
<span id="L229" class="LineNr"> 229 </span>  <span class="Delimiter">}</span>
<span id="L230" class="LineNr"> 230 </span>]
<span id="L231" class="LineNr"> 231 </span>
<span id="L232" class="LineNr"> 232 </span><span class="muScenario">scenario</span> editor-can-undo-typing-multiple [
<span id="L233" class="LineNr"> 233 </span>  <span class="Constant">local-scope</span>
<span id="L234" class="LineNr"> 234 </span>  <span class="Comment"># create an editor and type multiple characters</span>
<span id="L235" class="LineNr"> 235 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L236" class="LineNr"> 236 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L237" class="LineNr"> 237 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L238" class="LineNr"> 238 </span>  assume-console [
<span id="L239" class="LineNr"> 239 </span>  <span class="Conceal">¦</span> type <span class="Constant">[012]</span>
<span id="L240" class="LineNr"> 240 </span>  ]
<span id="L241" class="LineNr"> 241 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L242" class="LineNr"> 242 </span>  <span class="Comment"># undo</span>
<span id="L243" class="LineNr"> 243 </span>  assume-console [
<span id="L244" class="LineNr"> 244 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L245" class="LineNr"> 245 </span>  ]
<span id="L246" class="LineNr"> 246 </span>  run [
<span id="L247" class="LineNr"> 247 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L248" class="LineNr"> 248 </span>  ]
<span id="L249" class="LineNr"> 249 </span>  <span class="Comment"># all characters must be gone</span>
<span id="L250" class="LineNr"> 250 </span>  screen-should-contain [
<span id="L251" class="LineNr"> 251 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L252" class="LineNr"> 252 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L253" class="LineNr"> 253 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L254" class="LineNr"> 254 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L255" class="LineNr"> 255 </span>  ]
<span id="L256" class="LineNr"> 256 </span>]
<span id="L257" class="LineNr"> 257 </span>
<span id="L258" class="LineNr"> 258 </span><span class="muScenario">scenario</span> editor-can-undo-typing-multiple-2 [
<span id="L259" class="LineNr"> 259 </span>  <span class="Constant">local-scope</span>
<span id="L260" class="LineNr"> 260 </span>  <span class="Comment"># create an editor with some text</span>
<span id="L261" class="LineNr"> 261 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L262" class="LineNr"> 262 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[a]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L263" class="LineNr"> 263 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L264" class="LineNr"> 264 </span>  <span class="Comment"># type some characters</span>
<span id="L265" class="LineNr"> 265 </span>  assume-console [
<span id="L266" class="LineNr"> 266 </span>  <span class="Conceal">¦</span> type <span class="Constant">[012]</span>
<span id="L267" class="LineNr"> 267 </span>  ]
<span id="L268" class="LineNr"> 268 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L269" class="LineNr"> 269 </span>  screen-should-contain [
<span id="L270" class="LineNr"> 270 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L271" class="LineNr"> 271 </span>  <span class="Conceal">¦</span><span class="Constant"> .012a      .</span>
<span id="L272" class="LineNr"> 272 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L273" class="LineNr"> 273 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L274" class="LineNr"> 274 </span>  ]
<span id="L275" class="LineNr"> 275 </span>  <span class="Comment"># undo</span>
<span id="L276" class="LineNr"> 276 </span>  assume-console [
<span id="L277" class="LineNr"> 277 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L278" class="LineNr"> 278 </span>  ]
<span id="L279" class="LineNr"> 279 </span>  run [
<span id="L280" class="LineNr"> 280 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L281" class="LineNr"> 281 </span>  ]
<span id="L282" class="LineNr"> 282 </span>  <span class="Comment"># back to original text</span>
<span id="L283" class="LineNr"> 283 </span>  screen-should-contain [
<span id="L284" class="LineNr"> 284 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L285" class="LineNr"> 285 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
<span id="L286" class="LineNr"> 286 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L287" class="LineNr"> 287 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L288" class="LineNr"> 288 </span>  ]
<span id="L289" class="LineNr"> 289 </span>  <span class="Comment"># cursor should be in the right place</span>
<span id="L290" class="LineNr"> 290 </span>  assume-console [
<span id="L291" class="LineNr"> 291 </span>  <span class="Conceal">¦</span> type <span class="Constant">[3]</span>
<span id="L292" class="LineNr"> 292 </span>  ]
<span id="L293" class="LineNr"> 293 </span>  run [
<span id="L294" class="LineNr"> 294 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L295" class="LineNr"> 295 </span>  ]
<span id="L296" class="LineNr"> 296 </span>  screen-should-contain [
<span id="L297" class="LineNr"> 297 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L298" class="LineNr"> 298 </span>  <span class="Conceal">¦</span><span class="Constant"> .3a        .</span>
<span id="L299" class="LineNr"> 299 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L300" class="LineNr"> 300 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L301" class="LineNr"> 301 </span>  ]
<span id="L302" class="LineNr"> 302 </span>]
<span id="L303" class="LineNr"> 303 </span>
<span id="L304" class="LineNr"> 304 </span><span class="muScenario">scenario</span> editor-can-undo-typing-enter [
<span id="L305" class="LineNr"> 305 </span>  <span class="Constant">local-scope</span>
<span id="L306" class="LineNr"> 306 </span>  <span class="Comment"># create an editor with some text</span>
<span id="L307" class="LineNr"> 307 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L308" class="LineNr"> 308 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[  abc]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L309" class="LineNr"> 309 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L310" class="LineNr"> 310 </span>  <span class="Comment"># new line</span>
<span id="L311" class="LineNr"> 311 </span>  assume-console [
<span id="L312" class="LineNr"> 312 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 8</span>
<span id="L313" class="LineNr"> 313 </span>  <span class="Conceal">¦</span> press enter
<span id="L314" class="LineNr"> 314 </span>  ]
<span id="L315" class="LineNr"> 315 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L316" class="LineNr"> 316 </span>  screen-should-contain [
<span id="L317" class="LineNr"> 317 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L318" class="LineNr"> 318 </span>  <span class="Conceal">¦</span><span class="Constant"> .  abc     .</span>
<span id="L319" class="LineNr"> 319 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L320" class="LineNr"> 320 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L321" class="LineNr"> 321 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L322" class="LineNr"> 322 </span>  ]
<span id="L323" class="LineNr"> 323 </span>  <span class="Comment"># line is indented</span>
<span id="L324" class="LineNr"> 324 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L325" class="LineNr"> 325 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L326" class="LineNr"> 326 </span>  memory-should-contain [
<span id="L327" class="LineNr"> 327 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L328" class="LineNr"> 328 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L329" class="LineNr"> 329 </span>  ]
<span id="L330" class="LineNr"> 330 </span>  <span class="Comment"># undo</span>
<span id="L331" class="LineNr"> 331 </span>  assume-console [
<span id="L332" class="LineNr"> 332 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L333" class="LineNr"> 333 </span>  ]
<span id="L334" class="LineNr"> 334 </span>  run [
<span id="L335" class="LineNr"> 335 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L336" class="LineNr"> 336 </span>  ]
<span id="L337" class="LineNr"> 337 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L338" class="LineNr"> 338 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L339" class="LineNr"> 339 </span>  memory-should-contain [
<span id="L340" class="LineNr"> 340 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L341" class="LineNr"> 341 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>
<span id="L342" class="LineNr"> 342 </span>  ]
<span id="L343" class="LineNr"> 343 </span>  <span class="Comment"># back to original text</span>
<span id="L344" class="LineNr"> 344 </span>  screen-should-contain [
<span id="L345" class="LineNr"> 345 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L346" class="LineNr"> 346 </span>  <span class="Conceal">¦</span><span class="Constant"> .  abc     .</span>
<span id="L347" class="LineNr"> 347 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L348" class="LineNr"> 348 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L349" class="LineNr"> 349 </span>  ]
<span id="L350" class="LineNr"> 350 </span>  <span class="Comment"># cursor should be at end of line</span>
<span id="L351" class="LineNr"> 351 </span>  assume-console [
<span id="L352" class="LineNr"> 352 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
<span id="L353" class="LineNr"> 353 </span>  ]
<span id="L354" class="LineNr"> 354 </span>  run [
<span id="L355" class="LineNr"> 355 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L356" class="LineNr"> 356 </span>  ]
<span id="L357" class="LineNr"> 357 </span>  screen-should-contain [
<span id="L358" class="LineNr"> 358 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L359" class="LineNr"> 359 </span>  <span class="Conceal">¦</span><span class="Constant"> .  abc1    .</span>
<span id="L360" class="LineNr"> 360 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L361" class="LineNr"> 361 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L362" class="LineNr"> 362 </span>  ]
<span id="L363" class="LineNr"> 363 </span>]
<span id="L364" class="LineNr"> 364 </span>
<span id="L365" class="LineNr"> 365 </span><span class="Comment"># redo typing</span>
<span id="L366" class="LineNr"> 366 </span>
<span id="L367" class="LineNr"> 367 </span><span class="muScenario">scenario</span> editor-redo-typing [
<span id="L368" class="LineNr"> 368 </span>  <span class="Constant">local-scope</span>
<span id="L369" class="LineNr"> 369 </span>  <span class="Comment"># create an editor, type something, undo</span>
<span id="L370" class="LineNr"> 370 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L371" class="LineNr"> 371 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[a]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L372" class="LineNr"> 372 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L373" class="LineNr"> 373 </span>  assume-console [
<span id="L374" class="LineNr"> 374 </span>  <span class="Conceal">¦</span> type <span class="Constant">[012]</span>
<span id="L375" class="LineNr"> 375 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L376" class="LineNr"> 376 </span>  ]
<span id="L377" class="LineNr"> 377 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L378" class="LineNr"> 378 </span>  screen-should-contain [
<span id="L379" class="LineNr"> 379 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L380" class="LineNr"> 380 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
<span id="L381" class="LineNr"> 381 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L382" class="LineNr"> 382 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L383" class="LineNr"> 383 </span>  ]
<span id="L384" class="LineNr"> 384 </span>  <span class="Comment"># redo</span>
<span id="L385" class="LineNr"> 385 </span>  assume-console [
<span id="L386" class="LineNr"> 386 </span>  <span class="Conceal">¦</span> press ctrl-y
<span id="L387" class="LineNr"> 387 </span>  ]
<span id="L388" class="LineNr"> 388 </span>  run [
<span id="L389" class="LineNr"> 389 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L390" class="LineNr"> 390 </span>  ]
<span id="L391" class="LineNr"> 391 </span>  <span class="Comment"># all characters must be back</span>
<span id="L392" class="LineNr"> 392 </span>  screen-should-contain [
<span id="L393" class="LineNr"> 393 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L394" class="LineNr"> 394 </span>  <span class="Conceal">¦</span><span class="Constant"> .012a      .</span>
<span id="L395" class="LineNr"> 395 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L396" class="LineNr"> 396 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L397" class="LineNr"> 397 </span>  ]
<span id="L398" class="LineNr"> 398 </span>  <span class="Comment"># cursor should be in the right place</span>
<span id="L399" class="LineNr"> 399 </span>  assume-console [
<span id="L400" class="LineNr"> 400 </span>  <span class="Conceal">¦</span> type <span class="Constant">[3]</span>
<span id="L401" class="LineNr"> 401 </span>  ]
<span id="L402" class="LineNr"> 402 </span>  run [
<span id="L403" class="LineNr"> 403 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L404" class="LineNr"> 404 </span>  ]
<span id="L405" class="LineNr"> 405 </span>  screen-should-contain [
<span id="L406" class="LineNr"> 406 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L407" class="LineNr"> 407 </span>  <span class="Conceal">¦</span><span class="Constant"> .0123a     .</span>
<span id="L408" class="LineNr"> 408 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L409" class="LineNr"> 409 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L410" class="LineNr"> 410 </span>  ]
<span id="L411" class="LineNr"> 411 </span>]
<span id="L412" class="LineNr"> 412 </span>
<span id="L413" class="LineNr"> 413 </span><span class="muRecipe">after</span> <span class="Constant"><a href='012-editor-undo.mu.html#L96'>&lt;handle-redo&gt;</a></span> [
<span id="L414" class="LineNr"> 414 </span>  <span class="Delimiter">{</span>
<span id="L415" class="LineNr"> 415 </span>  <span class="Conceal">¦</span> typing:<a href='012-editor-undo.mu.html#L11'>insert-operation</a>, is-insert?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">typing:variant</span>
<span id="L416" class="LineNr"> 416 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-insert?
<span id="L417" class="LineNr"> 417 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L418" class="LineNr"> 418 </span>  <span class="Conceal">¦</span> insert-from:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get typing, <span class="Constant">insert-from:offset</span>  <span class="Comment"># ignore insert-to because it's already been spliced away</span>
<span id="L419" class="LineNr"> 419 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert insert-to matches next(before-cursor)</span>
<span id="L420" class="LineNr"> 420 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L525'>splice</a> before-cursor, insert-from
<span id="L421" class="LineNr"> 421 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
<span id="L422" class="LineNr"> 422 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> get typing, <span class="Constant">after-row:offset</span>
<span id="L423" class="LineNr"> 423 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L424" class="LineNr"> 424 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> get typing, <span class="Constant">after-column:offset</span>
<span id="L425" class="LineNr"> 425 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L426" class="LineNr"> 426 </span>  <span class="Conceal">¦</span> top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get typing, <span class="Constant">after-top-of-screen:offset</span>
<span id="L427" class="LineNr"> 427 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top
<span id="L428" class="LineNr"> 428 </span>  <span class="Delimiter">}</span>
<span id="L429" class="LineNr"> 429 </span>]
<span id="L430" class="LineNr"> 430 </span>
<span id="L431" class="LineNr"> 431 </span><span class="muScenario">scenario</span> editor-redo-typing-empty [
<span id="L432" class="LineNr"> 432 </span>  <span class="Constant">local-scope</span>
<span id="L433" class="LineNr"> 433 </span>  <span class="Comment"># create an editor, type something, undo</span>
<span id="L434" class="LineNr"> 434 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L435" class="LineNr"> 435 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L436" class="LineNr"> 436 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L437" class="LineNr"> 437 </span>  assume-console [
<span id="L438" class="LineNr"> 438 </span>  <span class="Conceal">¦</span> type <span class="Constant">[012]</span>
<span id="L439" class="LineNr"> 439 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L440" class="LineNr"> 440 </span>  ]
<span id="L441" class="LineNr"> 441 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L442" class="LineNr"> 442 </span>  screen-should-contain [
<span id="L443" class="LineNr"> 443 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L444" class="LineNr"> 444 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L445" class="LineNr"> 445 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L446" class="LineNr"> 446 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L447" class="LineNr"> 447 </span>  ]
<span id="L448" class="LineNr"> 448 </span>  <span class="Comment"># redo</span>
<span id="L449" class="LineNr"> 449 </span>  assume-console [
<span id="L450" class="LineNr"> 450 </span>  <span class="Conceal">¦</span> press ctrl-y
<span id="L451" class="LineNr"> 451 </span>  ]
<span id="L452" class="LineNr"> 452 </span>  run [
<span id="L453" class="LineNr"> 453 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L454" class="LineNr"> 454 </span>  ]
<span id="L455" class="LineNr"> 455 </span>  <span class="Comment"># all characters must be back</span>
<span id="L456" class="LineNr"> 456 </span>  screen-should-contain [
<span id="L457" class="LineNr"> 457 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L458" class="LineNr"> 458 </span>  <span class="Conceal">¦</span><span class="Constant"> .012       .</span>
<span id="L459" class="LineNr"> 459 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L460" class="LineNr"> 460 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L461" class="LineNr"> 461 </span>  ]
<span id="L462" class="LineNr"> 462 </span>  <span class="Comment"># cursor should be in the right place</span>
<span id="L463" class="LineNr"> 463 </span>  assume-console [
<span id="L464" class="LineNr"> 464 </span>  <span class="Conceal">¦</span> type <span class="Constant">[3]</span>
<span id="L465" class="LineNr"> 465 </span>  ]
<span id="L466" class="LineNr"> 466 </span>  run [
<span id="L467" class="LineNr"> 467 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L468" class="LineNr"> 468 </span>  ]
<span id="L469" class="LineNr"> 469 </span>  screen-should-contain [
<span id="L470" class="LineNr"> 470 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L471" class="LineNr"> 471 </span>  <span class="Conceal">¦</span><span class="Constant"> .0123      .</span>
<span id="L472" class="LineNr"> 472 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L473" class="LineNr"> 473 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L474" class="LineNr"> 474 </span>  ]
<span id="L475" class="LineNr"> 475 </span>]
<span id="L476" class="LineNr"> 476 </span>
<span id="L477" class="LineNr"> 477 </span><span class="muScenario">scenario</span> editor-work-clears-redo-stack [
<span id="L478" class="LineNr"> 478 </span>  <span class="Constant">local-scope</span>
<span id="L479" class="LineNr"> 479 </span>  <span class="Comment"># create an editor with some text, do some work, undo</span>
<span id="L480" class="LineNr"> 480 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L481" class="LineNr"> 481 </span>  contents:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L482" class="LineNr"> 482 </span><span class="Constant">def</span>
<span id="L483" class="LineNr"> 483 </span><span class="Constant">ghi]</span>
<span id="L484" class="LineNr"> 484 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L485" class="LineNr"> 485 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L486" class="LineNr"> 486 </span>  assume-console [
<span id="L487" class="LineNr"> 487 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
<span id="L488" class="LineNr"> 488 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L489" class="LineNr"> 489 </span>  ]
<span id="L490" class="LineNr"> 490 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L491" class="LineNr"> 491 </span>  <span class="Comment"># do some more work</span>
<span id="L492" class="LineNr"> 492 </span>  assume-console [
<span id="L493" class="LineNr"> 493 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
<span id="L494" class="LineNr"> 494 </span>  ]
<span id="L495" class="LineNr"> 495 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L496" class="LineNr"> 496 </span>  screen-should-contain [
<span id="L497" class="LineNr"> 497 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L498" class="LineNr"> 498 </span>  <span class="Conceal">¦</span><span class="Constant"> .0abc      .</span>
<span id="L499" class="LineNr"> 499 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
<span id="L500" class="LineNr"> 500 </span>  <span class="Conceal">¦</span><span class="Constant"> .ghi       .</span>
<span id="L501" class="LineNr"> 501 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L502" class="LineNr"> 502 </span>  ]
<span id="L503" class="LineNr"> 503 </span>  <span class="Comment"># redo</span>
<span id="L504" class="LineNr"> 504 </span>  assume-console [
<span id="L505" class="LineNr"> 505 </span>  <span class="Conceal">¦</span> press ctrl-y
<span id="L506" class="LineNr"> 506 </span>  ]
<span id="L507" class="LineNr"> 507 </span>  run [
<span id="L508" class="LineNr"> 508 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L509" class="LineNr"> 509 </span>  ]
<span id="L510" class="LineNr"> 510 </span>  <span class="Comment"># nothing should happen</span>
<span id="L511" class="LineNr"> 511 </span>  screen-should-contain [
<span id="L512" class="LineNr"> 512 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L513" class="LineNr"> 513 </span>  <span class="Conceal">¦</span><span class="Constant"> .0abc      .</span>
<span id="L514" class="LineNr"> 514 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
<span id="L515" class="LineNr"> 515 </span>  <span class="Conceal">¦</span><span class="Constant"> .ghi       .</span>
<span id="L516" class="LineNr"> 516 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L517" class="LineNr"> 517 </span>  ]
<span id="L518" class="LineNr"> 518 </span>]
<span id="L519" class="LineNr"> 519 </span>
<span id="L520" class="LineNr"> 520 </span><span class="muScenario">scenario</span> editor-can-redo-typing-and-enter-and-tab [
<span id="L521" class="LineNr"> 521 </span>  <span class="Constant">local-scope</span>
<span id="L522" class="LineNr"> 522 </span>  <span class="Comment"># create an editor</span>
<span id="L523" class="LineNr"> 523 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L524" class="LineNr"> 524 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L525" class="LineNr"> 525 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L526" class="LineNr"> 526 </span>  <span class="Comment"># insert some text and tabs, hit enter, some more text and tabs</span>
<span id="L527" class="LineNr"> 527 </span>  assume-console [
<span id="L528" class="LineNr"> 528 </span>  <span class="Conceal">¦</span> press tab
<span id="L529" class="LineNr"> 529 </span>  <span class="Conceal">¦</span> type <span class="Constant">[ab]</span>
<span id="L530" class="LineNr"> 530 </span>  <span class="Conceal">¦</span> press tab
<span id="L531" class="LineNr"> 531 </span>  <span class="Conceal">¦</span> type <span class="Constant">[cd]</span>
<span id="L532" class="LineNr"> 532 </span>  <span class="Conceal">¦</span> press enter
<span id="L533" class="LineNr"> 533 </span>  <span class="Conceal">¦</span> press tab
<span id="L534" class="LineNr"> 534 </span>  <span class="Conceal">¦</span> type <span class="Constant">[efg]</span>
<span id="L535" class="LineNr"> 535 </span>  ]
<span id="L536" class="LineNr"> 536 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L537" class="LineNr"> 537 </span>  screen-should-contain [
<span id="L538" class="LineNr"> 538 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L539" class="LineNr"> 539 </span>  <span class="Conceal">¦</span><span class="Constant"> .  ab  cd  .</span>
<span id="L540" class="LineNr"> 540 </span>  <span class="Conceal">¦</span><span class="Constant"> .    efg   .</span>
<span id="L541" class="LineNr"> 541 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L542" class="LineNr"> 542 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L543" class="LineNr"> 543 </span>  ]
<span id="L544" class="LineNr"> 544 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L545" class="LineNr"> 545 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L546" class="LineNr"> 546 </span>  memory-should-contain [
<span id="L547" class="LineNr"> 547 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L548" class="LineNr"> 548 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 7</span>
<span id="L549" class="LineNr"> 549 </span>  ]
<span id="L550" class="LineNr"> 550 </span>  <span class="Comment"># undo</span>
<span id="L551" class="LineNr"> 551 </span>  assume-console [
<span id="L552" class="LineNr"> 552 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L553" class="LineNr"> 553 </span>  ]
<span id="L554" class="LineNr"> 554 </span>  run [
<span id="L555" class="LineNr"> 555 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L556" class="LineNr"> 556 </span>  ]
<span id="L557" class="LineNr"> 557 </span>  <span class="Comment"># typing in second line deleted, but not indent</span>
<span id="L558" class="LineNr"> 558 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L559" class="LineNr"> 559 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L560" class="LineNr"> 560 </span>  memory-should-contain [
<span id="L561" class="LineNr"> 561 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L562" class="LineNr"> 562 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L563" class="LineNr"> 563 </span>  ]
<span id="L564" class="LineNr"> 564 </span>  screen-should-contain [
<span id="L565" class="LineNr"> 565 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L566" class="LineNr"> 566 </span>  <span class="Conceal">¦</span><span class="Constant"> .  ab  cd  .</span>
<span id="L567" class="LineNr"> 567 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L568" class="LineNr"> 568 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L569" class="LineNr"> 569 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L570" class="LineNr"> 570 </span>  ]
<span id="L571" class="LineNr"> 571 </span>  <span class="Comment"># undo again</span>
<span id="L572" class="LineNr"> 572 </span>  assume-console [
<span id="L573" class="LineNr"> 573 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L574" class="LineNr"> 574 </span>  ]
<span id="L575" class="LineNr"> 575 </span>  run [
<span id="L576" class="LineNr"> 576 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L577" class="LineNr"> 577 </span>  ]
<span id="L578" class="LineNr"> 578 </span>  <span class="Comment"># indent and newline deleted</span>
<span id="L579" class="LineNr"> 579 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L580" class="LineNr"> 580 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L581" class="LineNr"> 581 </span>  memory-should-contain [
<span id="L582" class="LineNr"> 582 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L583" class="LineNr"> 583 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 8</span>
<span id="L584" class="LineNr"> 584 </span>  ]
<span id="L585" class="LineNr"> 585 </span>  screen-should-contain [
<span id="L586" class="LineNr"> 586 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L587" class="LineNr"> 587 </span>  <span class="Conceal">¦</span><span class="Constant"> .  ab  cd  .</span>
<span id="L588" class="LineNr"> 588 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L589" class="LineNr"> 589 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L590" class="LineNr"> 590 </span>  ]
<span id="L591" class="LineNr"> 591 </span>  <span class="Comment"># undo again</span>
<span id="L592" class="LineNr"> 592 </span>  assume-console [
<span id="L593" class="LineNr"> 593 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L594" class="LineNr"> 594 </span>  ]
<span id="L595" class="LineNr"> 595 </span>  run [
<span id="L596" class="LineNr"> 596 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L597" class="LineNr"> 597 </span>  ]
<span id="L598" class="LineNr"> 598 </span>  <span class="Comment"># empty screen</span>
<span id="L599" class="LineNr"> 599 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L600" class="LineNr"> 600 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L601" class="LineNr"> 601 </span>  memory-should-contain [
<span id="L602" class="LineNr"> 602 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L603" class="LineNr"> 603 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L604" class="LineNr"> 604 </span>  ]
<span id="L605" class="LineNr"> 605 </span>  screen-should-contain [
<span id="L606" class="LineNr"> 606 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L607" class="LineNr"> 607 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L608" class="LineNr"> 608 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L609" class="LineNr"> 609 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L610" class="LineNr"> 610 </span>  ]
<span id="L611" class="LineNr"> 611 </span>  <span class="Comment"># redo</span>
<span id="L612" class="LineNr"> 612 </span>  assume-console [
<span id="L613" class="LineNr"> 613 </span>  <span class="Conceal">¦</span> press ctrl-y
<span id="L614" class="LineNr"> 614 </span>  ]
<span id="L615" class="LineNr"> 615 </span>  run [
<span id="L616" class="LineNr"> 616 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L617" class="LineNr"> 617 </span>  ]
<span id="L618" class="LineNr"> 618 </span>  <span class="Comment"># first line inserted</span>
<span id="L619" class="LineNr"> 619 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L620" class="LineNr"> 620 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L621" class="LineNr"> 621 </span>  memory-should-contain [
<span id="L622" class="LineNr"> 622 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L623" class="LineNr"> 623 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 8</span>
<span id="L624" class="LineNr"> 624 </span>  ]
<span id="L625" class="LineNr"> 625 </span>  screen-should-contain [
<span id="L626" class="LineNr"> 626 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L627" class="LineNr"> 627 </span>  <span class="Conceal">¦</span><span class="Constant"> .  ab  cd  .</span>
<span id="L628" class="LineNr"> 628 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L629" class="LineNr"> 629 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L630" class="LineNr"> 630 </span>  ]
<span id="L631" class="LineNr"> 631 </span>  <span class="Comment"># redo again</span>
<span id="L632" class="LineNr"> 632 </span>  assume-console [
<span id="L633" class="LineNr"> 633 </span>  <span class="Conceal">¦</span> press ctrl-y
<span id="L634" class="LineNr"> 634 </span>  ]
<span id="L635" class="LineNr"> 635 </span>  run [
<span id="L636" class="LineNr"> 636 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L637" class="LineNr"> 637 </span>  ]
<span id="L638" class="LineNr"> 638 </span>  <span class="Comment"># newline and indent inserted</span>
<span id="L639" class="LineNr"> 639 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L640" class="LineNr"> 640 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L641" class="LineNr"> 641 </span>  memory-should-contain [
<span id="L642" class="LineNr"> 642 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L643" class="LineNr"> 643 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L644" class="LineNr"> 644 </span>  ]
<span id="L645" class="LineNr"> 645 </span>  screen-should-contain [
<span id="L646" class="LineNr"> 646 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L647" class="LineNr"> 647 </span>  <span class="Conceal">¦</span><span class="Constant"> .  ab  cd  .</span>
<span id="L648" class="LineNr"> 648 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L649" class="LineNr"> 649 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L650" class="LineNr"> 650 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L651" class="LineNr"> 651 </span>  ]
<span id="L652" class="LineNr"> 652 </span>  <span class="Comment"># redo again</span>
<span id="L653" class="LineNr"> 653 </span>  assume-console [
<span id="L654" class="LineNr"> 654 </span>  <span class="Conceal">¦</span> press ctrl-y
<span id="L655" class="LineNr"> 655 </span>  ]
<span id="L656" class="LineNr"> 656 </span>  run [
<span id="L657" class="LineNr"> 657 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L658" class="LineNr"> 658 </span>  ]
<span id="L659" class="LineNr"> 659 </span>  <span class="Comment"># indent and newline deleted</span>
<span id="L660" class="LineNr"> 660 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L661" class="LineNr"> 661 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L662" class="LineNr"> 662 </span>  memory-should-contain [
<span id="L663" class="LineNr"> 663 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L664" class="LineNr"> 664 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 7</span>
<span id="L665" class="LineNr"> 665 </span>  ]
<span id="L666" class="LineNr"> 666 </span>  screen-should-contain [
<span id="L667" class="LineNr"> 667 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L668" class="LineNr"> 668 </span>  <span class="Conceal">¦</span><span class="Constant"> .  ab  cd  .</span>
<span id="L669" class="LineNr"> 669 </span>  <span class="Conceal">¦</span><span class="Constant"> .    efg   .</span>
<span id="L670" class="LineNr"> 670 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L671" class="LineNr"> 671 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L672" class="LineNr"> 672 </span>  ]
<span id="L673" class="LineNr"> 673 </span>]
<span id="L674" class="LineNr"> 674 </span>
<span id="L675" class="LineNr"> 675 </span><span class="Comment"># undo cursor movement and scroll</span>
<span id="L676" class="LineNr"> 676 </span>
<span id="L677" class="LineNr"> 677 </span><span class="muScenario">scenario</span> editor-can-undo-touch [
<span id="L678" class="LineNr"> 678 </span>  <span class="Constant">local-scope</span>
<span id="L679" class="LineNr"> 679 </span>  <span class="Comment"># create an editor with some text</span>
<span id="L680" class="LineNr"> 680 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L681" class="LineNr"> 681 </span>  contents:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L682" class="LineNr"> 682 </span><span class="Constant">def</span>
<span id="L683" class="LineNr"> 683 </span><span class="Constant">ghi]</span>
<span id="L684" class="LineNr"> 684 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L685" class="LineNr"> 685 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L686" class="LineNr"> 686 </span>  <span class="Comment"># move the cursor</span>
<span id="L687" class="LineNr"> 687 </span>  assume-console [
<span id="L688" class="LineNr"> 688 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 1</span>
<span id="L689" class="LineNr"> 689 </span>  ]
<span id="L690" class="LineNr"> 690 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L691" class="LineNr"> 691 </span>  <span class="Comment"># undo</span>
<span id="L692" class="LineNr"> 692 </span>  assume-console [
<span id="L693" class="LineNr"> 693 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L694" class="LineNr"> 694 </span>  ]
<span id="L695" class="LineNr"> 695 </span>  run [
<span id="L696" class="LineNr"> 696 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L697" class="LineNr"> 697 </span>  ]
<span id="L698" class="LineNr"> 698 </span>  <span class="Comment"># click undone</span>
<span id="L699" class="LineNr"> 699 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L700" class="LineNr"> 700 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L701" class="LineNr"> 701 </span>  memory-should-contain [
<span id="L702" class="LineNr"> 702 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L703" class="LineNr"> 703 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L704" class="LineNr"> 704 </span>  ]
<span id="L705" class="LineNr"> 705 </span>  <span class="Comment"># cursor should be in the right place</span>
<span id="L706" class="LineNr"> 706 </span>  assume-console [
<span id="L707" class="LineNr"> 707 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
<span id="L708" class="LineNr"> 708 </span>  ]
<span id="L709" class="LineNr"> 709 </span>  run [
<span id="L710" class="LineNr"> 710 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L711" class="LineNr"> 711 </span>  ]
<span id="L712" class="LineNr"> 712 </span>  screen-should-contain [
<span id="L713" class="LineNr"> 713 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L714" class="LineNr"> 714 </span>  <span class="Conceal">¦</span><span class="Constant"> .1abc      .</span>
<span id="L715" class="LineNr"> 715 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
<span id="L716" class="LineNr"> 716 </span>  <span class="Conceal">¦</span><span class="Constant"> .ghi       .</span>
<span id="L717" class="LineNr"> 717 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L718" class="LineNr"> 718 </span>  ]
<span id="L719" class="LineNr"> 719 </span>]
<span id="L720" class="LineNr"> 720 </span>
<span id="L721" class="LineNr"> 721 </span><span class="muRecipe">after</span> <span class="Constant">&lt;begin-move-cursor&gt;</span> [
<span id="L722" class="LineNr"> 722 </span>  cursor-row-before:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L723" class="LineNr"> 723 </span>  cursor-column-before:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L724" class="LineNr"> 724 </span>  top-before:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L725" class="LineNr"> 725 </span>]
<span id="L726" class="LineNr"> 726 </span><span class="muRecipe">before</span> <span class="Constant">&lt;end-move-cursor&gt;</span> [
<span id="L727" class="LineNr"> 727 </span>  top-after:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L728" class="LineNr"> 728 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L729" class="LineNr"> 729 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L730" class="LineNr"> 730 </span>  <span class="Delimiter">{</span>
<span id="L731" class="LineNr"> 731 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> undo-coalesce-tag
<span id="L732" class="LineNr"> 732 </span>  <span class="Conceal">¦</span> <span class="Comment"># if previous operation was also a move, and also had the same coalesce</span>
<span id="L733" class="LineNr"> 733 </span>  <span class="Conceal">¦</span> <span class="Comment"># tag, coalesce with it</span>
<span id="L734" class="LineNr"> 734 </span>  <span class="Conceal">¦</span> undo:&amp;:<a href='../064list.mu.html#L6'>list</a>:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
<span id="L735" class="LineNr"> 735 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> undo
<span id="L736" class="LineNr"> 736 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first undo
<span id="L737" class="LineNr"> 737 </span>  <span class="Conceal">¦</span> move:<a href='012-editor-undo.mu.html#L26'>move-operation</a>, is-move?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">move:variant</span>
<span id="L738" class="LineNr"> 738 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-move?
<span id="L739" class="LineNr"> 739 </span>  <span class="Conceal">¦</span> previous-coalesce-tag:num <span class="Special">&lt;-</span> get move, <span class="Constant">tag:offset</span>
<span id="L740" class="LineNr"> 740 </span>  <span class="Conceal">¦</span> coalesce?:bool <span class="Special">&lt;-</span> equal undo-coalesce-tag, previous-coalesce-tag
<span id="L741" class="LineNr"> 741 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> coalesce?
<span id="L742" class="LineNr"> 742 </span>  <span class="Conceal">¦</span> move <span class="Special">&lt;-</span> put move, <span class="Constant">after-row:offset</span>, cursor-row
<span id="L743" class="LineNr"> 743 </span>  <span class="Conceal">¦</span> move <span class="Special">&lt;-</span> put move, <span class="Constant">after-column:offset</span>, cursor-column
<span id="L744" class="LineNr"> 744 </span>  <span class="Conceal">¦</span> move <span class="Special">&lt;-</span> put move, <span class="Constant">after-top-of-screen:offset</span>, top-after
<span id="L745" class="LineNr"> 745 </span>  <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">1/move-operation</span>, move
<span id="L746" class="LineNr"> 746 </span>  <span class="Conceal">¦</span> <span class="muControl">break</span> <span class="Constant">+done-adding-move-operation</span>
<span id="L747" class="LineNr"> 747 </span>  <span class="Delimiter">}</span>
<span id="L748" class="LineNr"> 748 </span>  op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
<span id="L749" class="LineNr"> 749 </span>  *op <span class="Special">&lt;-</span> merge <span class="Constant">1/move-operation</span>, cursor-row-before, cursor-column-before, top-before, cursor-row/after, cursor-column/after, top-after, undo-coalesce-tag
<span id="L750" class="LineNr"> 750 </span>  editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L202'>add-operation</a> editor, op
<span id="L751" class="LineNr"> 751 </span><span class="Constant">  +done-adding-move-operation</span>
<span id="L752" class="LineNr"> 752 </span>]
<span id="L753" class="LineNr"> 753 </span>
<span id="L754" class="LineNr"> 754 </span><span class="muRecipe">after</span> <span class="Constant"><a href='012-editor-undo.mu.html#L78'>&lt;handle-undo&gt;</a></span> [
<span id="L755" class="LineNr"> 755 </span>  <span class="Delimiter">{</span>
<span id="L756" class="LineNr"> 756 </span>  <span class="Conceal">¦</span> move:<a href='012-editor-undo.mu.html#L26'>move-operation</a>, is-move?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">move:variant</span>
<span id="L757" class="LineNr"> 757 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-move?
<span id="L758" class="LineNr"> 758 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
<span id="L759" class="LineNr"> 759 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> get move, <span class="Constant">before-row:offset</span>
<span id="L760" class="LineNr"> 760 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L761" class="LineNr"> 761 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> get move, <span class="Constant">before-column:offset</span>
<span id="L762" class="LineNr"> 762 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L763" class="LineNr"> 763 </span>  <span class="Conceal">¦</span> top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get move, <span class="Constant">before-top-of-screen:offset</span>
<span id="L764" class="LineNr"> 764 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top
<span id="L765" class="LineNr"> 765 </span>  <span class="Delimiter">}</span>
<span id="L766" class="LineNr"> 766 </span>]
<span id="L767" class="LineNr"> 767 </span>
<span id="L768" class="LineNr"> 768 </span><span class="muScenario">scenario</span> editor-can-undo-scroll [
<span id="L769" class="LineNr"> 769 </span>  <span class="Constant">local-scope</span>
<span id="L770" class="LineNr"> 770 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L771" class="LineNr"> 771 </span>  assume-screen <span class="Constant">5/width</span>, <span class="Constant">4/height</span>
<span id="L772" class="LineNr"> 772 </span>  <span class="Comment"># editor contains a wrapped line</span>
<span id="L773" class="LineNr"> 773 </span>  contents:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L774" class="LineNr"> 774 </span><span class="Constant">b</span>
<span id="L775" class="LineNr"> 775 </span><span class="Constant">cdefgh]</span>
<span id="L776" class="LineNr"> 776 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L777" class="LineNr"> 777 </span>  <span class="Comment"># position cursor at end of screen and try to move right</span>
<span id="L778" class="LineNr"> 778 </span>  assume-console [
<span id="L779" class="LineNr"> 779 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 3</span>
<span id="L780" class="LineNr"> 780 </span>  <span class="Conceal">¦</span> press right-arrow
<span id="L781" class="LineNr"> 781 </span>  ]
<span id="L782" class="LineNr"> 782 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L783" class="LineNr"> 783 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L784" class="LineNr"> 784 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L785" class="LineNr"> 785 </span>  <span class="Comment"># screen scrolls</span>
<span id="L786" class="LineNr"> 786 </span>  screen-should-contain [
<span id="L787" class="LineNr"> 787 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
<span id="L788" class="LineNr"> 788 </span>  <span class="Conceal">¦</span><span class="Constant"> .b    .</span>
<span id="L789" class="LineNr"> 789 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .cdef↩.</span>
<span id="L790" class="LineNr"> 790 </span>  <span class="Conceal">¦</span><span class="Constant"> .gh   .</span>
<span id="L791" class="LineNr"> 791 </span>  ]
<span id="L792" class="LineNr"> 792 </span>  memory-should-contain [
<span id="L793" class="LineNr"> 793 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L794" class="LineNr"> 794 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L795" class="LineNr"> 795 </span>  ]
<span id="L796" class="LineNr"> 796 </span>  <span class="Comment"># undo</span>
<span id="L797" class="LineNr"> 797 </span>  assume-console [
<span id="L798" class="LineNr"> 798 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L799" class="LineNr"> 799 </span>  ]
<span id="L800" class="LineNr"> 800 </span>  run [
<span id="L801" class="LineNr"> 801 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L802" class="LineNr"> 802 </span>  ]
<span id="L803" class="LineNr"> 803 </span>  <span class="Comment"># cursor moved back</span>
<span id="L804" class="LineNr"> 804 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L805" class="LineNr"> 805 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L806" class="LineNr"> 806 </span>  memory-should-contain [
<span id="L807" class="LineNr"> 807 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L808" class="LineNr"> 808 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L809" class="LineNr"> 809 </span>  ]
<span id="L810" class="LineNr"> 810 </span>  <span class="Comment"># scroll undone</span>
<span id="L811" class="LineNr"> 811 </span>  screen-should-contain [
<span id="L812" class="LineNr"> 812 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
<span id="L813" class="LineNr"> 813 </span>  <span class="Conceal">¦</span><span class="Constant"> .a    .</span>
<span id="L814" class="LineNr"> 814 </span>  <span class="Conceal">¦</span><span class="Constant"> .b    .</span>
<span id="L815" class="LineNr"> 815 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .cdef↩.</span>
<span id="L816" class="LineNr"> 816 </span>  ]
<span id="L817" class="LineNr"> 817 </span>  <span class="Comment"># cursor should be in the right place</span>
<span id="L818" class="LineNr"> 818 </span>  assume-console [
<span id="L819" class="LineNr"> 819 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
<span id="L820" class="LineNr"> 820 </span>  ]
<span id="L821" class="LineNr"> 821 </span>  run [
<span id="L822" class="LineNr"> 822 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L823" class="LineNr"> 823 </span>  ]
<span id="L824" class="LineNr"> 824 </span>  screen-should-contain [
<span id="L825" class="LineNr"> 825 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
<span id="L826" class="LineNr"> 826 </span>  <span class="Conceal">¦</span><span class="Constant"> .b    .</span>
<span id="L827" class="LineNr"> 827 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .cde1↩.</span>
<span id="L828" class="LineNr"> 828 </span>  <span class="Conceal">¦</span><span class="Constant"> .fgh  .</span>
<span id="L829" class="LineNr"> 829 </span>  ]
<span id="L830" class="LineNr"> 830 </span>]
<span id="L831" class="LineNr"> 831 </span>
<span id="L832" class="LineNr"> 832 </span><span class="muScenario">scenario</span> editor-can-undo-left-arrow [
<span id="L833" class="LineNr"> 833 </span>  <span class="Constant">local-scope</span>
<span id="L834" class="LineNr"> 834 </span>  <span class="Comment"># create an editor with some text</span>
<span id="L835" class="LineNr"> 835 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L836" class="LineNr"> 836 </span>  contents:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L837" class="LineNr"> 837 </span><span class="Constant">def</span>
<span id="L838" class="LineNr"> 838 </span><span class="Constant">ghi]</span>
<span id="L839" class="LineNr"> 839 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L840" class="LineNr"> 840 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L841" class="LineNr"> 841 </span>  <span class="Comment"># move the cursor</span>
<span id="L842" class="LineNr"> 842 </span>  assume-console [
<span id="L843" class="LineNr"> 843 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 1</span>
<span id="L844" class="LineNr"> 844 </span>  <span class="Conceal">¦</span> press left-arrow
<span id="L845" class="LineNr"> 845 </span>  ]
<span id="L846" class="LineNr"> 846 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L847" class="LineNr"> 847 </span>  <span class="Comment"># undo</span>
<span id="L848" class="LineNr"> 848 </span>  assume-console [
<span id="L849" class="LineNr"> 849 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L850" class="LineNr"> 850 </span>  ]
<span id="L851" class="LineNr"> 851 </span>  run [
<span id="L852" class="LineNr"> 852 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L853" class="LineNr"> 853 </span>  ]
<span id="L854" class="LineNr"> 854 </span>  <span class="Comment"># cursor moves back</span>
<span id="L855" class="LineNr"> 855 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L856" class="LineNr"> 856 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L857" class="LineNr"> 857 </span>  memory-should-contain [
<span id="L858" class="LineNr"> 858 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L859" class="LineNr"> 859 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L860" class="LineNr"> 860 </span>  ]
<span id="L861" class="LineNr"> 861 </span>  <span class="Comment"># cursor should be in the right place</span>
<span id="L862" class="LineNr"> 862 </span>  assume-console [
<span id="L863" class="LineNr"> 863 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
<span id="L864" class="LineNr"> 864 </span>  ]
<span id="L865" class="LineNr"> 865 </span>  run [
<span id="L866" class="LineNr"> 866 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L867" class="LineNr"> 867 </span>  ]
<span id="L868" class="LineNr"> 868 </span>  screen-should-contain [
<span id="L869" class="LineNr"> 869 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L870" class="LineNr"> 870 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
<span id="L871" class="LineNr"> 871 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
<span id="L872" class="LineNr"> 872 </span>  <span class="Conceal">¦</span><span class="Constant"> .g1hi      .</span>
<span id="L873" class="LineNr"> 873 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L874" class="LineNr"> 874 </span>  ]
<span id="L875" class="LineNr"> 875 </span>]
<span id="L876" class="LineNr"> 876 </span>
<span id="L877" class="LineNr"> 877 </span><span class="muScenario">scenario</span> editor-can-undo-up-arrow [
<span id="L878" class="LineNr"> 878 </span>  <span class="Constant">local-scope</span>
<span id="L879" class="LineNr"> 879 </span>  <span class="Comment"># create an editor with some text</span>
<span id="L880" class="LineNr"> 880 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L881" class="LineNr"> 881 </span>  contents:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L882" class="LineNr"> 882 </span><span class="Constant">def</span>
<span id="L883" class="LineNr"> 883 </span><span class="Constant">ghi]</span>
<span id="L884" class="LineNr"> 884 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L885" class="LineNr"> 885 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L886" class="LineNr"> 886 </span>  <span class="Comment"># move the cursor</span>
<span id="L887" class="LineNr"> 887 </span>  assume-console [
<span id="L888" class="LineNr"> 888 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 1</span>
<span id="L889" class="LineNr"> 889 </span>  <span class="Conceal">¦</span> press up-arrow
<span id="L890" class="LineNr"> 890 </span>  ]
<span id="L891" class="LineNr"> 891 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L892" class="LineNr"> 892 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L893" class="LineNr"> 893 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L894" class="LineNr"> 894 </span>  memory-should-contain [
<span id="L895" class="LineNr"> 895 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L896" class="LineNr"> 896 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L897" class="LineNr"> 897 </span>  ]
<span id="L898" class="LineNr"> 898 </span>  <span class="Comment"># undo</span>
<span id="L899" class="LineNr"> 899 </span>  assume-console [
<span id="L900" class="LineNr"> 900 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L901" class="LineNr"> 901 </span>  ]
<span id="L902" class="LineNr"> 902 </span>  run [
<span id="L903" class="LineNr"> 903 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L904" class="LineNr"> 904 </span>  ]
<span id="L905" class="LineNr"> 905 </span>  <span class="Comment"># cursor moves back</span>
<span id="L906" class="LineNr"> 906 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L907" class="LineNr"> 907 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L908" class="LineNr"> 908 </span>  memory-should-contain [
<span id="L909" class="LineNr"> 909 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L910" class="LineNr"> 910 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L911" class="LineNr"> 911 </span>  ]
<span id="L912" class="LineNr"> 912 </span>  <span class="Comment"># cursor should be in the right place</span>
<span id="L913" class="LineNr"> 913 </span>  assume-console [
<span id="L914" class="LineNr"> 914 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
<span id="L915" class="LineNr"> 915 </span>  ]
<span id="L916" class="LineNr"> 916 </span>  run [
<span id="L917" class="LineNr"> 917 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L918" class="LineNr"> 918 </span>  ]
<span id="L919" class="LineNr"> 919 </span>  screen-should-contain [
<span id="L920" class="LineNr"> 920 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L921" class="LineNr"> 921 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
<span id="L922" class="LineNr"> 922 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
<span id="L923" class="LineNr"> 923 </span>  <span class="Conceal">¦</span><span class="Constant"> .g1hi      .</span>
<span id="L924" class="LineNr"> 924 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L925" class="LineNr"> 925 </span>  ]
<span id="L926" class="LineNr"> 926 </span>]
<span id="L927" class="LineNr"> 927 </span>
<span id="L928" class="LineNr"> 928 </span><span class="muScenario">scenario</span> editor-can-undo-down-arrow [
<span id="L929" class="LineNr"> 929 </span>  <span class="Constant">local-scope</span>
<span id="L930" class="LineNr"> 930 </span>  <span class="Comment"># create an editor with some text</span>
<span id="L931" class="LineNr"> 931 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L932" class="LineNr"> 932 </span>  contents:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L933" class="LineNr"> 933 </span><span class="Constant">def</span>
<span id="L934" class="LineNr"> 934 </span><span class="Constant">ghi]</span>
<span id="L935" class="LineNr"> 935 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L936" class="LineNr"> 936 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L937" class="LineNr"> 937 </span>  <span class="Comment"># move the cursor</span>
<span id="L938" class="LineNr"> 938 </span>  assume-console [
<span id="L939" class="LineNr"> 939 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
<span id="L940" class="LineNr"> 940 </span>  <span class="Conceal">¦</span> press down-arrow
<span id="L941" class="LineNr"> 941 </span>  ]
<span id="L942" class="LineNr"> 942 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L943" class="LineNr"> 943 </span>  <span class="Comment"># undo</span>
<span id="L944" class="LineNr"> 944 </span>  assume-console [
<span id="L945" class="LineNr"> 945 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L946" class="LineNr"> 946 </span>  ]
<span id="L947" class="LineNr"> 947 </span>  run [
<span id="L948" class="LineNr"> 948 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L949" class="LineNr"> 949 </span>  ]
<span id="L950" class="LineNr"> 950 </span>  <span class="Comment"># cursor moves back</span>
<span id="L951" class="LineNr"> 951 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L952" class="LineNr"> 952 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L953" class="LineNr"> 953 </span>  memory-should-contain [
<span id="L954" class="LineNr"> 954 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L955" class="LineNr"> 955 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L956" class="LineNr"> 956 </span>  ]
<span id="L957" class="LineNr"> 957 </span>  <span class="Comment"># cursor should be in the right place</span>
<span id="L958" class="LineNr"> 958 </span>  assume-console [
<span id="L959" class="LineNr"> 959 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
<span id="L960" class="LineNr"> 960 </span>  ]
<span id="L961" class="LineNr"> 961 </span>  run [
<span id="L962" class="LineNr"> 962 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L963" class="LineNr"> 963 </span>  ]
<span id="L964" class="LineNr"> 964 </span>  screen-should-contain [
<span id="L965" class="LineNr"> 965 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L966" class="LineNr"> 966 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
<span id="L967" class="LineNr"> 967 </span>  <span class="Conceal">¦</span><span class="Constant"> .d1ef      .</span>
<span id="L968" class="LineNr"> 968 </span>  <span class="Conceal">¦</span><span class="Constant"> .ghi       .</span>
<span id="L969" class="LineNr"> 969 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L970" class="LineNr"> 970 </span>  ]
<span id="L971" class="LineNr"> 971 </span>]
<span id="L972" class="LineNr"> 972 </span>
<span id="L973" class="LineNr"> 973 </span><span class="muScenario">scenario</span> editor-can-undo-ctrl-f [
<span id="L974" class="LineNr"> 974 </span>  <span class="Constant">local-scope</span>
<span id="L975" class="LineNr"> 975 </span>  <span class="Comment"># create an editor with multiple pages of text</span>
<span id="L976" class="LineNr"> 976 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L977" class="LineNr"> 977 </span>  contents:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L978" class="LineNr"> 978 </span><span class="Constant">b</span>
<span id="L979" class="LineNr"> 979 </span><span class="Constant">c</span>
<span id="L980" class="LineNr"> 980 </span><span class="Constant">d</span>
<span id="L981" class="LineNr"> 981 </span><span class="Constant">e</span>
<span id="L982" class="LineNr"> 982 </span><span class="Constant">f]</span>
<span id="L983" class="LineNr"> 983 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L984" class="LineNr"> 984 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L985" class="LineNr"> 985 </span>  <span class="Comment"># scroll the page</span>
<span id="L986" class="LineNr"> 986 </span>  assume-console [
<span id="L987" class="LineNr"> 987 </span>  <span class="Conceal">¦</span> press ctrl-f
<span id="L988" class="LineNr"> 988 </span>  ]
<span id="L989" class="LineNr"> 989 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L990" class="LineNr"> 990 </span>  <span class="Comment"># undo</span>
<span id="L991" class="LineNr"> 991 </span>  assume-console [
<span id="L992" class="LineNr"> 992 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L993" class="LineNr"> 993 </span>  ]
<span id="L994" class="LineNr"> 994 </span>  run [
<span id="L995" class="LineNr"> 995 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L996" class="LineNr"> 996 </span>  ]
<span id="L997" class="LineNr"> 997 </span>  <span class="Comment"># screen should again show page 1</span>
<span id="L998" class="LineNr"> 998 </span>  screen-should-contain [
<span id="L999" class="LineNr"> 999 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1000" class="LineNr">1000 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
<span id="L1001" class="LineNr">1001 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
<span id="L1002" class="LineNr">1002 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
<span id="L1003" class="LineNr">1003 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
<span id="L1004" class="LineNr">1004 </span>  ]
<span id="L1005" class="LineNr">1005 </span>]
<span id="L1006" class="LineNr">1006 </span>
<span id="L1007" class="LineNr">1007 </span><span class="muScenario">scenario</span> editor-can-undo-page-down [
<span id="L1008" class="LineNr">1008 </span>  <span class="Constant">local-scope</span>
<span id="L1009" class="LineNr">1009 </span>  <span class="Comment"># create an editor with multiple pages of text</span>
<span id="L1010" class="LineNr">1010 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1011" class="LineNr">1011 </span>  contents:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L1012" class="LineNr">1012 </span><span class="Constant">b</span>
<span id="L1013" class="LineNr">1013 </span><span class="Constant">c</span>
<span id="L1014" class="LineNr">1014 </span><span class="Constant">d</span>
<span id="L1015" class="LineNr">1015 </span><span class="Constant">e</span>
<span id="L1016" class="LineNr">1016 </span><span class="Constant">f]</span>
<span id="L1017" class="LineNr">1017 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1018" class="LineNr">1018 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1019" class="LineNr">1019 </span>  <span class="Comment"># scroll the page</span>
<span id="L1020" class="LineNr">1020 </span>  assume-console [
<span id="L1021" class="LineNr">1021 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L3597'>page-down</a>
<span id="L1022" class="LineNr">1022 </span>  ]
<span id="L1023" class="LineNr">1023 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1024" class="LineNr">1024 </span>  <span class="Comment"># undo</span>
<span id="L1025" class="LineNr">1025 </span>  assume-console [
<span id="L1026" class="LineNr">1026 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L1027" class="LineNr">1027 </span>  ]
<span id="L1028" class="LineNr">1028 </span>  run [
<span id="L1029" class="LineNr">1029 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1030" class="LineNr">1030 </span>  ]
<span id="L1031" class="LineNr">1031 </span>  <span class="Comment"># screen should again show page 1</span>
<span id="L1032" class="LineNr">1032 </span>  screen-should-contain [
<span id="L1033" class="LineNr">1033 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1034" class="LineNr">1034 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
<span id="L1035" class="LineNr">1035 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
<span id="L1036" class="LineNr">1036 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
<span id="L1037" class="LineNr">1037 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
<span id="L1038" class="LineNr">1038 </span>  ]
<span id="L1039" class="LineNr">1039 </span>]
<span id="L1040" class="LineNr">1040 </span>
<span id="L1041" class="LineNr">1041 </span><span class="muScenario">scenario</span> editor-can-undo-ctrl-b [
<span id="L1042" class="LineNr">1042 </span>  <span class="Constant">local-scope</span>
<span id="L1043" class="LineNr">1043 </span>  <span class="Comment"># create an editor with multiple pages of text</span>
<span id="L1044" class="LineNr">1044 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1045" class="LineNr">1045 </span>  contents:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L1046" class="LineNr">1046 </span><span class="Constant">b</span>
<span id="L1047" class="LineNr">1047 </span><span class="Constant">c</span>
<span id="L1048" class="LineNr">1048 </span><span class="Constant">d</span>
<span id="L1049" class="LineNr">1049 </span><span class="Constant">e</span>
<span id="L1050" class="LineNr">1050 </span><span class="Constant">f]</span>
<span id="L1051" class="LineNr">1051 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1052" class="LineNr">1052 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1053" class="LineNr">1053 </span>  <span class="Comment"># scroll the page down and up</span>
<span id="L1054" class="LineNr">1054 </span>  assume-console [
<span id="L1055" class="LineNr">1055 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L3597'>page-down</a>
<span id="L1056" class="LineNr">1056 </span>  <span class="Conceal">¦</span> press ctrl-b
<span id="L1057" class="LineNr">1057 </span>  ]
<span id="L1058" class="LineNr">1058 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1059" class="LineNr">1059 </span>  <span class="Comment"># undo</span>
<span id="L1060" class="LineNr">1060 </span>  assume-console [
<span id="L1061" class="LineNr">1061 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L1062" class="LineNr">1062 </span>  ]
<span id="L1063" class="LineNr">1063 </span>  run [
<span id="L1064" class="LineNr">1064 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1065" class="LineNr">1065 </span>  ]
<span id="L1066" class="LineNr">1066 </span>  <span class="Comment"># screen should again show page 2</span>
<span id="L1067" class="LineNr">1067 </span>  screen-should-contain [
<span id="L1068" class="LineNr">1068 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1069" class="LineNr">1069 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
<span id="L1070" class="LineNr">1070 </span>  <span class="Conceal">¦</span><span class="Constant"> .e         .</span>
<span id="L1071" class="LineNr">1071 </span>  <span class="Conceal">¦</span><span class="Constant"> .f         .</span>
<span id="L1072" class="LineNr">1072 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1073" class="LineNr">1073 </span>  ]
<span id="L1074" class="LineNr">1074 </span>]
<span id="L1075" class="LineNr">1075 </span>
<span id="L1076" class="LineNr">1076 </span><span class="muScenario">scenario</span> editor-can-undo-page-up [
<span id="L1077" class="LineNr">1077 </span>  <span class="Constant">local-scope</span>
<span id="L1078" class="LineNr">1078 </span>  <span class="Comment"># create an editor with multiple pages of text</span>
<span id="L1079" class="LineNr">1079 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1080" class="LineNr">1080 </span>  contents:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L1081" class="LineNr">1081 </span><span class="Constant">b</span>
<span id="L1082" class="LineNr">1082 </span><span class="Constant">c</span>
<span id="L1083" class="LineNr">1083 </span><span class="Constant">d</span>
<span id="L1084" class="LineNr">1084 </span><span class="Constant">e</span>
<span id="L1085" class="LineNr">1085 </span><span class="Constant">f]</span>
<span id="L1086" class="LineNr">1086 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1087" class="LineNr">1087 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1088" class="LineNr">1088 </span>  <span class="Comment"># scroll the page down and up</span>
<span id="L1089" class="LineNr">1089 </span>  assume-console [
<span id="L1090" class="LineNr">1090 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L3597'>page-down</a>
<span id="L1091" class="LineNr">1091 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L3820'>page-up</a>
<span id="L1092" class="LineNr">1092 </span>  ]
<span id="L1093" class="LineNr">1093 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1094" class="LineNr">1094 </span>  <span class="Comment"># undo</span>
<span id="L1095" class="LineNr">1095 </span>  assume-console [
<span id="L1096" class="LineNr">1096 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L1097" class="LineNr">1097 </span>  ]
<span id="L1098" class="LineNr">1098 </span>  run [
<span id="L1099" class="LineNr">1099 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1100" class="LineNr">1100 </span>  ]
<span id="L1101" class="LineNr">1101 </span>  <span class="Comment"># screen should again show page 2</span>
<span id="L1102" class="LineNr">1102 </span>  screen-should-contain [
<span id="L1103" class="LineNr">1103 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1104" class="LineNr">1104 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
<span id="L1105" class="LineNr">1105 </span>  <span class="Conceal">¦</span><span class="Constant"> .e         .</span>
<span id="L1106" class="LineNr">1106 </span>  <span class="Conceal">¦</span><span class="Constant"> .f         .</span>
<span id="L1107" class="LineNr">1107 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1108" class="LineNr">1108 </span>  ]
<span id="L1109" class="LineNr">1109 </span>]
<span id="L1110" class="LineNr">1110 </span>
<span id="L1111" class="LineNr">1111 </span><span class="muScenario">scenario</span> editor-can-undo-ctrl-a [
<span id="L1112" class="LineNr">1112 </span>  <span class="Constant">local-scope</span>
<span id="L1113" class="LineNr">1113 </span>  <span class="Comment"># create an editor with some text</span>
<span id="L1114" class="LineNr">1114 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1115" class="LineNr">1115 </span>  contents:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L1116" class="LineNr">1116 </span><span class="Constant">def</span>
<span id="L1117" class="LineNr">1117 </span><span class="Constant">ghi]</span>
<span id="L1118" class="LineNr">1118 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1119" class="LineNr">1119 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1120" class="LineNr">1120 </span>  <span class="Comment"># move the cursor, then to start of line</span>
<span id="L1121" class="LineNr">1121 </span>  assume-console [
<span id="L1122" class="LineNr">1122 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
<span id="L1123" class="LineNr">1123 </span>  <span class="Conceal">¦</span> press ctrl-a
<span id="L1124" class="LineNr">1124 </span>  ]
<span id="L1125" class="LineNr">1125 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1126" class="LineNr">1126 </span>  <span class="Comment"># undo</span>
<span id="L1127" class="LineNr">1127 </span>  assume-console [
<span id="L1128" class="LineNr">1128 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L1129" class="LineNr">1129 </span>  ]
<span id="L1130" class="LineNr">1130 </span>  run [
<span id="L1131" class="LineNr">1131 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1132" class="LineNr">1132 </span>  ]
<span id="L1133" class="LineNr">1133 </span>  <span class="Comment"># cursor moves back</span>
<span id="L1134" class="LineNr">1134 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1135" class="LineNr">1135 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1136" class="LineNr">1136 </span>  memory-should-contain [
<span id="L1137" class="LineNr">1137 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1138" class="LineNr">1138 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1139" class="LineNr">1139 </span>  ]
<span id="L1140" class="LineNr">1140 </span>  <span class="Comment"># cursor should be in the right place</span>
<span id="L1141" class="LineNr">1141 </span>  assume-console [
<span id="L1142" class="LineNr">1142 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
<span id="L1143" class="LineNr">1143 </span>  ]
<span id="L1144" class="LineNr">1144 </span>  run [
<span id="L1145" class="LineNr">1145 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1146" class="LineNr">1146 </span>  ]
<span id="L1147" class="LineNr">1147 </span>  screen-should-contain [
<span id="L1148" class="LineNr">1148 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1149" class="LineNr">1149 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
<span id="L1150" class="LineNr">1150 </span>  <span class="Conceal">¦</span><span class="Constant"> .d1ef      .</span>
<span id="L1151" class="LineNr">1151 </span>  <span class="Conceal">¦</span><span class="Constant"> .ghi       .</span>
<span id="L1152" class="LineNr">1152 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1153" class="LineNr">1153 </span>  ]
<span id="L1154" class="LineNr">1154 </span>]
<span id="L1155" class="LineNr">1155 </span>
<span id="L1156" class="LineNr">1156 </span><span class="muScenario">scenario</span> editor-can-undo-home [
<span id="L1157" class="LineNr">1157 </span>  <span class="Constant">local-scope</span>
<span id="L1158" class="LineNr">1158 </span>  <span class="Comment"># create an editor with some text</span>
<span id="L1159" class="LineNr">1159 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1160" class="LineNr">1160 </span>  contents:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L1161" class="LineNr">1161 </span><span class="Constant">def</span>
<span id="L1162" class="LineNr">1162 </span><span class="Constant">ghi]</span>
<span id="L1163" class="LineNr">1163 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1164" class="LineNr">1164 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1165" class="LineNr">1165 </span>  <span class="Comment"># move the cursor, then to start of line</span>
<span id="L1166" class="LineNr">1166 </span>  assume-console [
<span id="L1167" class="LineNr">1167 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
<span id="L1168" class="LineNr">1168 </span>  <span class="Conceal">¦</span> press home
<span id="L1169" class="LineNr">1169 </span>  ]
<span id="L1170" class="LineNr">1170 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1171" class="LineNr">1171 </span>  <span class="Comment"># undo</span>
<span id="L1172" class="LineNr">1172 </span>  assume-console [
<span id="L1173" class="LineNr">1173 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L1174" class="LineNr">1174 </span>  ]
<span id="L1175" class="LineNr">1175 </span>  run [
<span id="L1176" class="LineNr">1176 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1177" class="LineNr">1177 </span>  ]
<span id="L1178" class="LineNr">1178 </span>  <span class="Comment"># cursor moves back</span>
<span id="L1179" class="LineNr">1179 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1180" class="LineNr">1180 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1181" class="LineNr">1181 </span>  memory-should-contain [
<span id="L1182" class="LineNr">1182 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1183" class="LineNr">1183 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1184" class="LineNr">1184 </span>  ]
<span id="L1185" class="LineNr">1185 </span>  <span class="Comment"># cursor should be in the right place</span>
<span id="L1186" class="LineNr">1186 </span>  assume-console [
<span id="L1187" class="LineNr">1187 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
<span id="L1188" class="LineNr">1188 </span>  ]
<span id="L1189" class="LineNr">1189 </span>  run [
<span id="L1190" class="LineNr">1190 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1191" class="LineNr">1191 </span>  ]
<span id="L1192" class="LineNr">1192 </span>  screen-should-contain [
<span id="L1193" class="LineNr">1193 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1194" class="LineNr">1194 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
<span id="L1195" class="LineNr">1195 </span>  <span class="Conceal">¦</span><span class="Constant"> .d1ef      .</span>
<span id="L1196" class="LineNr">1196 </span>  <span class="Conceal">¦</span><span class="Constant"> .ghi       .</span>
<span id="L1197" class="LineNr">1197 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1198" class="LineNr">1198 </span>  ]
<span id="L1199" class="LineNr">1199 </span>]
<span id="L1200" class="LineNr">1200 </span>
<span id="L1201" class="LineNr">1201 </span><span class="muScenario">scenario</span> editor-can-undo-ctrl-e [
<span id="L1202" class="LineNr">1202 </span>  <span class="Constant">local-scope</span>
<span id="L1203" class="LineNr">1203 </span>  <span class="Comment"># create an editor with some text</span>
<span id="L1204" class="LineNr">1204 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1205" class="LineNr">1205 </span>  contents:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L1206" class="LineNr">1206 </span><span class="Constant">def</span>
<span id="L1207" class="LineNr">1207 </span><span class="Constant">ghi]</span>
<span id="L1208" class="LineNr">1208 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1209" class="LineNr">1209 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1210" class="LineNr">1210 </span>  <span class="Comment"># move the cursor, then to start of line</span>
<span id="L1211" class="LineNr">1211 </span>  assume-console [
<span id="L1212" class="LineNr">1212 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
<span id="L1213" class="LineNr">1213 </span>  <span class="Conceal">¦</span> press ctrl-e
<span id="L1214" class="LineNr">1214 </span>  ]
<span id="L1215" class="LineNr">1215 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1216" class="LineNr">1216 </span>  <span class="Comment"># undo</span>
<span id="L1217" class="LineNr">1217 </span>  assume-console [
<span id="L1218" class="LineNr">1218 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L1219" class="LineNr">1219 </span>  ]
<span id="L1220" class="LineNr">1220 </span>  run [
<span id="L1221" class="LineNr">1221 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1222" class="LineNr">1222 </span>  ]
<span id="L1223" class="LineNr">1223 </span>  <span class="Comment"># cursor moves back</span>
<span id="L1224" class="LineNr">1224 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1225" class="LineNr">1225 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1226" class="LineNr">1226 </span>  memory-should-contain [
<span id="L1227" class="LineNr">1227 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1228" class="LineNr">1228 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1229" class="LineNr">1229 </span>  ]
<span id="L1230" class="LineNr">1230 </span>  <span class="Comment"># cursor should be in the right place</span>
<span id="L1231" class="LineNr">1231 </span>  assume-console [
<span id="L1232" class="LineNr">1232 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
<span id="L1233" class="LineNr">1233 </span>  ]
<span id="L1234" class="LineNr">1234 </span>  run [
<span id="L1235" class="LineNr">1235 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1236" class="LineNr">1236 </span>  ]
<span id="L1237" class="LineNr">1237 </span>  screen-should-contain [
<span id="L1238" class="LineNr">1238 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1239" class="LineNr">1239 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
<span id="L1240" class="LineNr">1240 </span>  <span class="Conceal">¦</span><span class="Constant"> .d1ef      .</span>
<span id="L1241" class="LineNr">1241 </span>  <span class="Conceal">¦</span><span class="Constant"> .ghi       .</span>
<span id="L1242" class="LineNr">1242 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1243" class="LineNr">1243 </span>  ]
<span id="L1244" class="LineNr">1244 </span>]
<span id="L1245" class="LineNr">1245 </span>
<span id="L1246" class="LineNr">1246 </span><span class="muScenario">scenario</span> editor-can-undo-end [
<span id="L1247" class="LineNr">1247 </span>  <span class="Constant">local-scope</span>
<span id="L1248" class="LineNr">1248 </span>  <span class="Comment"># create an editor with some text</span>
<span id="L1249" class="LineNr">1249 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1250" class="LineNr">1250 </span>  contents:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L1251" class="LineNr">1251 </span><span class="Constant">def</span>
<span id="L1252" class="LineNr">1252 </span><span class="Constant">ghi]</span>
<span id="L1253" class="LineNr">1253 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1254" class="LineNr">1254 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1255" class="LineNr">1255 </span>  <span class="Comment"># move the cursor, then to start of line</span>
<span id="L1256" class="LineNr">1256 </span>  assume-console [
<span id="L1257" class="LineNr">1257 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
<span id="L1258" class="LineNr">1258 </span>  <span class="Conceal">¦</span> press end
<span id="L1259" class="LineNr">1259 </span>  ]
<span id="L1260" class="LineNr">1260 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1261" class="LineNr">1261 </span>  <span class="Comment"># undo</span>
<span id="L1262" class="LineNr">1262 </span>  assume-console [
<span id="L1263" class="LineNr">1263 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L1264" class="LineNr">1264 </span>  ]
<span id="L1265" class="LineNr">1265 </span>  run [
<span id="L1266" class="LineNr">1266 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1267" class="LineNr">1267 </span>  ]
<span id="L1268" class="LineNr">1268 </span>  <span class="Comment"># cursor moves back</span>
<span id="L1269" class="LineNr">1269 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1270" class="LineNr">1270 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1271" class="LineNr">1271 </span>  memory-should-contain [
<span id="L1272" class="LineNr">1272 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1273" class="LineNr">1273 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1274" class="LineNr">1274 </span>  ]
<span id="L1275" class="LineNr">1275 </span>  <span class="Comment"># cursor should be in the right place</span>
<span id="L1276" class="LineNr">1276 </span>  assume-console [
<span id="L1277" class="LineNr">1277 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
<span id="L1278" class="LineNr">1278 </span>  ]
<span id="L1279" class="LineNr">1279 </span>  run [
<span id="L1280" class="LineNr">1280 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1281" class="LineNr">1281 </span>  ]
<span id="L1282" class="LineNr">1282 </span>  screen-should-contain [
<span id="L1283" class="LineNr">1283 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1284" class="LineNr">1284 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
<span id="L1285" class="LineNr">1285 </span>  <span class="Conceal">¦</span><span class="Constant"> .d1ef      .</span>
<span id="L1286" class="LineNr">1286 </span>  <span class="Conceal">¦</span><span class="Constant"> .ghi       .</span>
<span id="L1287" class="LineNr">1287 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1288" class="LineNr">1288 </span>  ]
<span id="L1289" class="LineNr">1289 </span>]
<span id="L1290" class="LineNr">1290 </span>
<span id="L1291" class="LineNr">1291 </span><span class="muScenario">scenario</span> editor-can-undo-multiple-arrows-in-the-same-direction [
<span id="L1292" class="LineNr">1292 </span>  <span class="Constant">local-scope</span>
<span id="L1293" class="LineNr">1293 </span>  <span class="Comment"># create an editor with some text</span>
<span id="L1294" class="LineNr">1294 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1295" class="LineNr">1295 </span>  contents:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L1296" class="LineNr">1296 </span><span class="Constant">def</span>
<span id="L1297" class="LineNr">1297 </span><span class="Constant">ghi]</span>
<span id="L1298" class="LineNr">1298 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1299" class="LineNr">1299 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1300" class="LineNr">1300 </span>  <span class="Comment"># move the cursor</span>
<span id="L1301" class="LineNr">1301 </span>  assume-console [
<span id="L1302" class="LineNr">1302 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
<span id="L1303" class="LineNr">1303 </span>  <span class="Conceal">¦</span> press right-arrow
<span id="L1304" class="LineNr">1304 </span>  <span class="Conceal">¦</span> press right-arrow
<span id="L1305" class="LineNr">1305 </span>  <span class="Conceal">¦</span> press up-arrow
<span id="L1306" class="LineNr">1306 </span>  ]
<span id="L1307" class="LineNr">1307 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1308" class="LineNr">1308 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1309" class="LineNr">1309 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1310" class="LineNr">1310 </span>  memory-should-contain [
<span id="L1311" class="LineNr">1311 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1312" class="LineNr">1312 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L1313" class="LineNr">1313 </span>  ]
<span id="L1314" class="LineNr">1314 </span>  <span class="Comment"># undo</span>
<span id="L1315" class="LineNr">1315 </span>  assume-console [
<span id="L1316" class="LineNr">1316 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L1317" class="LineNr">1317 </span>  ]
<span id="L1318" class="LineNr">1318 </span>  run [
<span id="L1319" class="LineNr">1319 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1320" class="LineNr">1320 </span>  ]
<span id="L1321" class="LineNr">1321 </span>  <span class="Comment"># up-arrow is undone</span>
<span id="L1322" class="LineNr">1322 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1323" class="LineNr">1323 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1324" class="LineNr">1324 </span>  memory-should-contain [
<span id="L1325" class="LineNr">1325 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1326" class="LineNr">1326 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L1327" class="LineNr">1327 </span>  ]
<span id="L1328" class="LineNr">1328 </span>  <span class="Comment"># undo again</span>
<span id="L1329" class="LineNr">1329 </span>  assume-console [
<span id="L1330" class="LineNr">1330 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L1331" class="LineNr">1331 </span>  ]
<span id="L1332" class="LineNr">1332 </span>  run [
<span id="L1333" class="LineNr">1333 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1334" class="LineNr">1334 </span>  ]
<span id="L1335" class="LineNr">1335 </span>  <span class="Comment"># both right-arrows are undone</span>
<span id="L1336" class="LineNr">1336 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1337" class="LineNr">1337 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1338" class="LineNr">1338 </span>  memory-should-contain [
<span id="L1339" class="LineNr">1339 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1340" class="LineNr">1340 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1341" class="LineNr">1341 </span>  ]
<span id="L1342" class="LineNr">1342 </span>]
<span id="L1343" class="LineNr">1343 </span>
<span id="L1344" class="LineNr">1344 </span><span class="Comment"># redo cursor movement and scroll</span>
<span id="L1345" class="LineNr">1345 </span>
<span id="L1346" class="LineNr">1346 </span><span class="muScenario">scenario</span> editor-redo-touch [
<span id="L1347" class="LineNr">1347 </span>  <span class="Constant">local-scope</span>
<span id="L1348" class="LineNr">1348 </span>  <span class="Comment"># create an editor with some text, click on a character, undo</span>
<span id="L1349" class="LineNr">1349 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1350" class="LineNr">1350 </span>  contents:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L1351" class="LineNr">1351 </span><span class="Constant">def</span>
<span id="L1352" class="LineNr">1352 </span><span class="Constant">ghi]</span>
<span id="L1353" class="LineNr">1353 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1354" class="LineNr">1354 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1355" class="LineNr">1355 </span>  assume-console [
<span id="L1356" class="LineNr">1356 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 1</span>
<span id="L1357" class="LineNr">1357 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L1358" class="LineNr">1358 </span>  ]
<span id="L1359" class="LineNr">1359 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1360" class="LineNr">1360 </span>  <span class="Comment"># redo</span>
<span id="L1361" class="LineNr">1361 </span>  assume-console [
<span id="L1362" class="LineNr">1362 </span>  <span class="Conceal">¦</span> press ctrl-y
<span id="L1363" class="LineNr">1363 </span>  ]
<span id="L1364" class="LineNr">1364 </span>  run [
<span id="L1365" class="LineNr">1365 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1366" class="LineNr">1366 </span>  ]
<span id="L1367" class="LineNr">1367 </span>  <span class="Comment"># cursor moves to left-click</span>
<span id="L1368" class="LineNr">1368 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1369" class="LineNr">1369 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1370" class="LineNr">1370 </span>  memory-should-contain [
<span id="L1371" class="LineNr">1371 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L1372" class="LineNr">1372 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1373" class="LineNr">1373 </span>  ]
<span id="L1374" class="LineNr">1374 </span>  <span class="Comment"># cursor should be in the right place</span>
<span id="L1375" class="LineNr">1375 </span>  assume-console [
<span id="L1376" class="LineNr">1376 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
<span id="L1377" class="LineNr">1377 </span>  ]
<span id="L1378" class="LineNr">1378 </span>  run [
<span id="L1379" class="LineNr">1379 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1380" class="LineNr">1380 </span>  ]
<span id="L1381" class="LineNr">1381 </span>  screen-should-contain [
<span id="L1382" class="LineNr">1382 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1383" class="LineNr">1383 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
<span id="L1384" class="LineNr">1384 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
<span id="L1385" class="LineNr">1385 </span>  <span class="Conceal">¦</span><span class="Constant"> .g1hi      .</span>
<span id="L1386" class="LineNr">1386 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1387" class="LineNr">1387 </span>  ]
<span id="L1388" class="LineNr">1388 </span>]
<span id="L1389" class="LineNr">1389 </span>
<span id="L1390" class="LineNr">1390 </span><span class="muRecipe">after</span> <span class="Constant"><a href='012-editor-undo.mu.html#L96'>&lt;handle-redo&gt;</a></span> [
<span id="L1391" class="LineNr">1391 </span>  <span class="Delimiter">{</span>
<span id="L1392" class="LineNr">1392 </span>  <span class="Conceal">¦</span> move:<a href='012-editor-undo.mu.html#L26'>move-operation</a>, is-move?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">move:variant</span>
<span id="L1393" class="LineNr">1393 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-move?
<span id="L1394" class="LineNr">1394 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
<span id="L1395" class="LineNr">1395 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> get move, <span class="Constant">after-row:offset</span>
<span id="L1396" class="LineNr">1396 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L1397" class="LineNr">1397 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> get move, <span class="Constant">after-column:offset</span>
<span id="L1398" class="LineNr">1398 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L1399" class="LineNr">1399 </span>  <span class="Conceal">¦</span> top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get move, <span class="Constant">after-top-of-screen:offset</span>
<span id="L1400" class="LineNr">1400 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top
<span id="L1401" class="LineNr">1401 </span>  <span class="Delimiter">}</span>
<span id="L1402" class="LineNr">1402 </span>]
<span id="L1403" class="LineNr">1403 </span>
<span id="L1404" class="LineNr">1404 </span><span class="muScenario">scenario</span> editor-separates-undo-insert-from-undo-cursor-move [
<span id="L1405" class="LineNr">1405 </span>  <span class="Constant">local-scope</span>
<span id="L1406" class="LineNr">1406 </span>  <span class="Comment"># create an editor, type some text, move the cursor, type some more text</span>
<span id="L1407" class="LineNr">1407 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1408" class="LineNr">1408 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1409" class="LineNr">1409 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1410" class="LineNr">1410 </span>  assume-console [
<span id="L1411" class="LineNr">1411 </span>  <span class="Conceal">¦</span> type <span class="Constant">[abc]</span>
<span id="L1412" class="LineNr">1412 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
<span id="L1413" class="LineNr">1413 </span>  <span class="Conceal">¦</span> type <span class="Constant">[d]</span>
<span id="L1414" class="LineNr">1414 </span>  ]
<span id="L1415" class="LineNr">1415 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1416" class="LineNr">1416 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1417" class="LineNr">1417 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1418" class="LineNr">1418 </span>  screen-should-contain [
<span id="L1419" class="LineNr">1419 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1420" class="LineNr">1420 </span>  <span class="Conceal">¦</span><span class="Constant"> .adbc      .</span>
<span id="L1421" class="LineNr">1421 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1422" class="LineNr">1422 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1423" class="LineNr">1423 </span>  ]
<span id="L1424" class="LineNr">1424 </span>  memory-should-contain [
<span id="L1425" class="LineNr">1425 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1426" class="LineNr">1426 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1427" class="LineNr">1427 </span>  ]
<span id="L1428" class="LineNr">1428 </span>  <span class="Comment"># undo</span>
<span id="L1429" class="LineNr">1429 </span>  assume-console [
<span id="L1430" class="LineNr">1430 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L1431" class="LineNr">1431 </span>  ]
<span id="L1432" class="LineNr">1432 </span>  run [
<span id="L1433" class="LineNr">1433 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1434" class="LineNr">1434 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1435" class="LineNr">1435 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1436" class="LineNr">1436 </span>  ]
<span id="L1437" class="LineNr">1437 </span>  <span class="Comment"># last letter typed is deleted</span>
<span id="L1438" class="LineNr">1438 </span>  screen-should-contain [
<span id="L1439" class="LineNr">1439 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1440" class="LineNr">1440 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
<span id="L1441" class="LineNr">1441 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1442" class="LineNr">1442 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1443" class="LineNr">1443 </span>  ]
<span id="L1444" class="LineNr">1444 </span>  memory-should-contain [
<span id="L1445" class="LineNr">1445 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1446" class="LineNr">1446 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1447" class="LineNr">1447 </span>  ]
<span id="L1448" class="LineNr">1448 </span>  <span class="Comment"># undo again</span>
<span id="L1449" class="LineNr">1449 </span>  assume-console [
<span id="L1450" class="LineNr">1450 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L1451" class="LineNr">1451 </span>  ]
<span id="L1452" class="LineNr">1452 </span>  run [
<span id="L1453" class="LineNr">1453 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1454" class="LineNr">1454 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1455" class="LineNr">1455 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1456" class="LineNr">1456 </span>  ]
<span id="L1457" class="LineNr">1457 </span>  <span class="Comment"># no change to screen; cursor moves</span>
<span id="L1458" class="LineNr">1458 </span>  screen-should-contain [
<span id="L1459" class="LineNr">1459 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1460" class="LineNr">1460 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
<span id="L1461" class="LineNr">1461 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1462" class="LineNr">1462 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1463" class="LineNr">1463 </span>  ]
<span id="L1464" class="LineNr">1464 </span>  memory-should-contain [
<span id="L1465" class="LineNr">1465 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1466" class="LineNr">1466 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L1467" class="LineNr">1467 </span>  ]
<span id="L1468" class="LineNr">1468 </span>  <span class="Comment"># undo again</span>
<span id="L1469" class="LineNr">1469 </span>  assume-console [
<span id="L1470" class="LineNr">1470 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L1471" class="LineNr">1471 </span>  ]
<span id="L1472" class="LineNr">1472 </span>  run [
<span id="L1473" class="LineNr">1473 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1474" class="LineNr">1474 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1475" class="LineNr">1475 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1476" class="LineNr">1476 </span>  ]
<span id="L1477" class="LineNr">1477 </span>  <span class="Comment"># screen empty</span>
<span id="L1478" class="LineNr">1478 </span>  screen-should-contain [
<span id="L1479" class="LineNr">1479 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1480" class="LineNr">1480 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1481" class="LineNr">1481 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1482" class="LineNr">1482 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1483" class="LineNr">1483 </span>  ]
<span id="L1484" class="LineNr">1484 </span>  memory-should-contain [
<span id="L1485" class="LineNr">1485 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1486" class="LineNr">1486 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1487" class="LineNr">1487 </span>  ]
<span id="L1488" class="LineNr">1488 </span>  <span class="Comment"># redo</span>
<span id="L1489" class="LineNr">1489 </span>  assume-console [
<span id="L1490" class="LineNr">1490 </span>  <span class="Conceal">¦</span> press ctrl-y
<span id="L1491" class="LineNr">1491 </span>  ]
<span id="L1492" class="LineNr">1492 </span>  run [
<span id="L1493" class="LineNr">1493 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1494" class="LineNr">1494 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1495" class="LineNr">1495 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1496" class="LineNr">1496 </span>  ]
<span id="L1497" class="LineNr">1497 </span>  <span class="Comment"># first insert</span>
<span id="L1498" class="LineNr">1498 </span>  screen-should-contain [
<span id="L1499" class="LineNr">1499 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1500" class="LineNr">1500 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
<span id="L1501" class="LineNr">1501 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1502" class="LineNr">1502 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1503" class="LineNr">1503 </span>  ]
<span id="L1504" class="LineNr">1504 </span>  memory-should-contain [
<span id="L1505" class="LineNr">1505 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1506" class="LineNr">1506 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L1507" class="LineNr">1507 </span>  ]
<span id="L1508" class="LineNr">1508 </span>  <span class="Comment"># redo again</span>
<span id="L1509" class="LineNr">1509 </span>  assume-console [
<span id="L1510" class="LineNr">1510 </span>  <span class="Conceal">¦</span> press ctrl-y
<span id="L1511" class="LineNr">1511 </span>  ]
<span id="L1512" class="LineNr">1512 </span>  run [
<span id="L1513" class="LineNr">1513 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1514" class="LineNr">1514 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1515" class="LineNr">1515 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1516" class="LineNr">1516 </span>  ]
<span id="L1517" class="LineNr">1517 </span>  <span class="Comment"># cursor moves</span>
<span id="L1518" class="LineNr">1518 </span>  screen-should-contain [
<span id="L1519" class="LineNr">1519 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1520" class="LineNr">1520 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
<span id="L1521" class="LineNr">1521 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1522" class="LineNr">1522 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1523" class="LineNr">1523 </span>  ]
<span id="L1524" class="LineNr">1524 </span>  <span class="Comment"># cursor moves</span>
<span id="L1525" class="LineNr">1525 </span>  memory-should-contain [
<span id="L1526" class="LineNr">1526 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1527" class="LineNr">1527 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1528" class="LineNr">1528 </span>  ]
<span id="L1529" class="LineNr">1529 </span>  <span class="Comment"># redo again</span>
<span id="L1530" class="LineNr">1530 </span>  assume-console [
<span id="L1531" class="LineNr">1531 </span>  <span class="Conceal">¦</span> press ctrl-y
<span id="L1532" class="LineNr">1532 </span>  ]
<span id="L1533" class="LineNr">1533 </span>  run [
<span id="L1534" class="LineNr">1534 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1535" class="LineNr">1535 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1536" class="LineNr">1536 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1537" class="LineNr">1537 </span>  ]
<span id="L1538" class="LineNr">1538 </span>  <span class="Comment"># second insert</span>
<span id="L1539" class="LineNr">1539 </span>  screen-should-contain [
<span id="L1540" class="LineNr">1540 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1541" class="LineNr">1541 </span>  <span class="Conceal">¦</span><span class="Constant"> .adbc      .</span>
<span id="L1542" class="LineNr">1542 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1543" class="LineNr">1543 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1544" class="LineNr">1544 </span>  ]
<span id="L1545" class="LineNr">1545 </span>  memory-should-contain [
<span id="L1546" class="LineNr">1546 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1547" class="LineNr">1547 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1548" class="LineNr">1548 </span>  ]
<span id="L1549" class="LineNr">1549 </span>]
<span id="L1550" class="LineNr">1550 </span>
<span id="L1551" class="LineNr">1551 </span><span class="Comment"># undo backspace</span>
<span id="L1552" class="LineNr">1552 </span>
<span id="L1553" class="LineNr">1553 </span><span class="muScenario">scenario</span> editor-can-undo-and-redo-backspace [
<span id="L1554" class="LineNr">1554 </span>  <span class="Constant">local-scope</span>
<span id="L1555" class="LineNr">1555 </span>  <span class="Comment"># create an editor</span>
<span id="L1556" class="LineNr">1556 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1557" class="LineNr">1557 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1558" class="LineNr">1558 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1559" class="LineNr">1559 </span>  <span class="Comment"># insert some text and hit backspace</span>
<span id="L1560" class="LineNr">1560 </span>  assume-console [
<span id="L1561" class="LineNr">1561 </span>  <span class="Conceal">¦</span> type <span class="Constant">[abc]</span>
<span id="L1562" class="LineNr">1562 </span>  <span class="Conceal">¦</span> press backspace
<span id="L1563" class="LineNr">1563 </span>  <span class="Conceal">¦</span> press backspace
<span id="L1564" class="LineNr">1564 </span>  ]
<span id="L1565" class="LineNr">1565 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1566" class="LineNr">1566 </span>  screen-should-contain [
<span id="L1567" class="LineNr">1567 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1568" class="LineNr">1568 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
<span id="L1569" class="LineNr">1569 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1570" class="LineNr">1570 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1571" class="LineNr">1571 </span>  ]
<span id="L1572" class="LineNr">1572 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1573" class="LineNr">1573 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1574" class="LineNr">1574 </span>  memory-should-contain [
<span id="L1575" class="LineNr">1575 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1576" class="LineNr">1576 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1577" class="LineNr">1577 </span>  ]
<span id="L1578" class="LineNr">1578 </span>  <span class="Comment"># undo</span>
<span id="L1579" class="LineNr">1579 </span>  assume-console [
<span id="L1580" class="LineNr">1580 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L1581" class="LineNr">1581 </span>  ]
<span id="L1582" class="LineNr">1582 </span>  run [
<span id="L1583" class="LineNr">1583 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1584" class="LineNr">1584 </span>  ]
<span id="L1585" class="LineNr">1585 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1586" class="LineNr">1586 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1587" class="LineNr">1587 </span>  memory-should-contain [
<span id="L1588" class="LineNr">1588 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1589" class="LineNr">1589 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L1590" class="LineNr">1590 </span>  ]
<span id="L1591" class="LineNr">1591 </span>  screen-should-contain [
<span id="L1592" class="LineNr">1592 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1593" class="LineNr">1593 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
<span id="L1594" class="LineNr">1594 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1595" class="LineNr">1595 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1596" class="LineNr">1596 </span>  ]
<span id="L1597" class="LineNr">1597 </span>  <span class="Comment"># redo</span>
<span id="L1598" class="LineNr">1598 </span>  assume-console [
<span id="L1599" class="LineNr">1599 </span>  <span class="Conceal">¦</span> press ctrl-y
<span id="L1600" class="LineNr">1600 </span>  ]
<span id="L1601" class="LineNr">1601 </span>  run [
<span id="L1602" class="LineNr">1602 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1603" class="LineNr">1603 </span>  ]
<span id="L1604" class="LineNr">1604 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1605" class="LineNr">1605 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1606" class="LineNr">1606 </span>  memory-should-contain [
<span id="L1607" class="LineNr">1607 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1608" class="LineNr">1608 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1609" class="LineNr">1609 </span>  ]
<span id="L1610" class="LineNr">1610 </span>  screen-should-contain [
<span id="L1611" class="LineNr">1611 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1612" class="LineNr">1612 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
<span id="L1613" class="LineNr">1613 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1614" class="LineNr">1614 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1615" class="LineNr">1615 </span>  ]
<span id="L1616" class="LineNr">1616 </span>]
<span id="L1617" class="LineNr">1617 </span>
<span id="L1618" class="LineNr">1618 </span><span class="Comment"># save operation to undo</span>
<span id="L1619" class="LineNr">1619 </span><span class="muRecipe">after</span> <span class="Constant"><a href='003-shortcuts.mu.html#L99'>&lt;begin-backspace-character&gt;</a></span> [
<span id="L1620" class="LineNr">1620 </span>  top-before:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L1621" class="LineNr">1621 </span>]
<span id="L1622" class="LineNr">1622 </span><span class="muRecipe">before</span> <span class="Constant"><a href='003-shortcuts.mu.html#L101'>&lt;end-backspace-character&gt;</a></span> [
<span id="L1623" class="LineNr">1623 </span>  <span class="Delimiter">{</span>
<span id="L1624" class="LineNr">1624 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> backspaced-cell  <span class="Comment"># backspace failed; don't add an undo operation</span>
<span id="L1625" class="LineNr">1625 </span>  <span class="Conceal">¦</span> top-after:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L1626" class="LineNr">1626 </span>  <span class="Conceal">¦</span> cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L1627" class="LineNr">1627 </span>  <span class="Conceal">¦</span> cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L1628" class="LineNr">1628 </span>  <span class="Conceal">¦</span> before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L1629" class="LineNr">1629 </span>  <span class="Conceal">¦</span> undo:&amp;:<a href='../064list.mu.html#L6'>list</a>:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
<span id="L1630" class="LineNr">1630 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
<span id="L1631" class="LineNr">1631 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># if previous operation was an insert, coalesce this operation with it</span>
<span id="L1632" class="LineNr">1632 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> undo
<span id="L1633" class="LineNr">1633 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first undo
<span id="L1634" class="LineNr">1634 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion:<a href='012-editor-undo.mu.html#L43'>delete-operation</a>, is-delete?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">delete:variant</span>
<span id="L1635" class="LineNr">1635 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-delete?
<span id="L1636" class="LineNr">1636 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> previous-coalesce-tag:num <span class="Special">&lt;-</span> get deletion, <span class="Constant">tag:offset</span>
<span id="L1637" class="LineNr">1637 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> coalesce?:bool <span class="Special">&lt;-</span> equal previous-coalesce-tag, <span class="Constant">1/coalesce-backspace</span>
<span id="L1638" class="LineNr">1638 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> coalesce?
<span id="L1639" class="LineNr">1639 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">delete-from:offset</span>, before-cursor
<span id="L1640" class="LineNr">1640 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> backspaced-so-far:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">deleted-text:offset</span>
<span id="L1641" class="LineNr">1641 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L525'>splice</a> backspaced-cell, backspaced-so-far
<span id="L1642" class="LineNr">1642 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">deleted-text:offset</span>, backspaced-cell
<span id="L1643" class="LineNr">1643 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-row:offset</span>, cursor-row
<span id="L1644" class="LineNr">1644 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-column:offset</span>, cursor-column
<span id="L1645" class="LineNr">1645 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-top-of-screen:offset</span>, top-after
<span id="L1646" class="LineNr">1646 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, deletion
<span id="L1647" class="LineNr">1647 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break</span> <span class="Constant">+done-adding-backspace-operation</span>
<span id="L1648" class="LineNr">1648 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
<span id="L1649" class="LineNr">1649 </span>  <span class="Conceal">¦</span> <span class="Comment"># if not, create a new operation</span>
<span id="L1650" class="LineNr">1650 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
<span id="L1651" class="LineNr">1651 </span>  <span class="Conceal">¦</span> deleted-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
<span id="L1652" class="LineNr">1652 </span>  <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, save-row/before, save-column/before, top-before, cursor-row/after, cursor-column/after, top-after, backspaced-cell/deleted, before-cursor/delete-from, deleted-until, <span class="Constant">1/coalesce-backspace</span>
<span id="L1653" class="LineNr">1653 </span>  <span class="Conceal">¦</span> editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L202'>add-operation</a> editor, op
<span id="L1654" class="LineNr">1654 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> +done-adding-backspace-operation</span>
<span id="L1655" class="LineNr">1655 </span>  <span class="Delimiter">}</span>
<span id="L1656" class="LineNr">1656 </span>]
<span id="L1657" class="LineNr">1657 </span>
<span id="L1658" class="LineNr">1658 </span><span class="muRecipe">after</span> <span class="Constant"><a href='012-editor-undo.mu.html#L78'>&lt;handle-undo&gt;</a></span> [
<span id="L1659" class="LineNr">1659 </span>  <span class="Delimiter">{</span>
<span id="L1660" class="LineNr">1660 </span>  <span class="Conceal">¦</span> deletion:<a href='012-editor-undo.mu.html#L43'>delete-operation</a>, is-delete?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">delete:variant</span>
<span id="L1661" class="LineNr">1661 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-delete?
<span id="L1662" class="LineNr">1662 </span>  <span class="Conceal">¦</span> anchor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">delete-from:offset</span>
<span id="L1663" class="LineNr">1663 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> anchor
<span id="L1664" class="LineNr">1664 </span>  <span class="Conceal">¦</span> deleted:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">deleted-text:offset</span>
<span id="L1665" class="LineNr">1665 </span>  <span class="Conceal">¦</span> old-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L572'>last</a> deleted
<span id="L1666" class="LineNr">1666 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L525'>splice</a> anchor, deleted
<span id="L1667" class="LineNr">1667 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
<span id="L1668" class="LineNr">1668 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy old-cursor
<span id="L1669" class="LineNr">1669 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> get deletion, <span class="Constant">before-row:offset</span>
<span id="L1670" class="LineNr">1670 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L1671" class="LineNr">1671 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> get deletion, <span class="Constant">before-column:offset</span>
<span id="L1672" class="LineNr">1672 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L1673" class="LineNr">1673 </span>  <span class="Conceal">¦</span> top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">before-top-of-screen:offset</span>
<span id="L1674" class="LineNr">1674 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top
<span id="L1675" class="LineNr">1675 </span>  <span class="Delimiter">}</span>
<span id="L1676" class="LineNr">1676 </span>]
<span id="L1677" class="LineNr">1677 </span>
<span id="L1678" class="LineNr">1678 </span><span class="muRecipe">after</span> <span class="Constant"><a href='012-editor-undo.mu.html#L96'>&lt;handle-redo&gt;</a></span> [
<span id="L1679" class="LineNr">1679 </span>  <span class="Delimiter">{</span>
<span id="L1680" class="LineNr">1680 </span>  <span class="Conceal">¦</span> deletion:<a href='012-editor-undo.mu.html#L43'>delete-operation</a>, is-delete?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">delete:variant</span>
<span id="L1681" class="LineNr">1681 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-delete?
<span id="L1682" class="LineNr">1682 </span>  <span class="Conceal">¦</span> start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">delete-from:offset</span>
<span id="L1683" class="LineNr">1683 </span>  <span class="Conceal">¦</span> end:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">delete-until:offset</span>
<span id="L1684" class="LineNr">1684 </span>  <span class="Conceal">¦</span> data:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
<span id="L1685" class="LineNr">1685 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L385'>remove-between</a> start, end
<span id="L1686" class="LineNr">1686 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
<span id="L1687" class="LineNr">1687 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> get deletion, <span class="Constant">after-row:offset</span>
<span id="L1688" class="LineNr">1688 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L1689" class="LineNr">1689 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> get deletion, <span class="Constant">after-column:offset</span>
<span id="L1690" class="LineNr">1690 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L1691" class="LineNr">1691 </span>  <span class="Conceal">¦</span> top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">before-top-of-screen:offset</span>
<span id="L1692" class="LineNr">1692 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top
<span id="L1693" class="LineNr">1693 </span>  <span class="Delimiter">}</span>
<span id="L1694" class="LineNr">1694 </span>]
<span id="L1695" class="LineNr">1695 </span>
<span id="L1696" class="LineNr">1696 </span><span class="Comment"># undo delete</span>
<span id="L1697" class="LineNr">1697 </span>
<span id="L1698" class="LineNr">1698 </span><span class="muScenario">scenario</span> editor-can-undo-and-redo-delete [
<span id="L1699" class="LineNr">1699 </span>  <span class="Constant">local-scope</span>
<span id="L1700" class="LineNr">1700 </span>  <span class="Comment"># create an editor</span>
<span id="L1701" class="LineNr">1701 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1702" class="LineNr">1702 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1703" class="LineNr">1703 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1704" class="LineNr">1704 </span>  <span class="Comment"># insert some text and hit delete and backspace a few times</span>
<span id="L1705" class="LineNr">1705 </span>  assume-console [
<span id="L1706" class="LineNr">1706 </span>  <span class="Conceal">¦</span> type <span class="Constant">[abcdef]</span>
<span id="L1707" class="LineNr">1707 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
<span id="L1708" class="LineNr">1708 </span>  <span class="Conceal">¦</span> press delete
<span id="L1709" class="LineNr">1709 </span>  <span class="Conceal">¦</span> press backspace
<span id="L1710" class="LineNr">1710 </span>  <span class="Conceal">¦</span> press delete
<span id="L1711" class="LineNr">1711 </span>  <span class="Conceal">¦</span> press delete
<span id="L1712" class="LineNr">1712 </span>  ]
<span id="L1713" class="LineNr">1713 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1714" class="LineNr">1714 </span>  screen-should-contain [
<span id="L1715" class="LineNr">1715 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1716" class="LineNr">1716 </span>  <span class="Conceal">¦</span><span class="Constant"> .af        .</span>
<span id="L1717" class="LineNr">1717 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1718" class="LineNr">1718 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1719" class="LineNr">1719 </span>  ]
<span id="L1720" class="LineNr">1720 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1721" class="LineNr">1721 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1722" class="LineNr">1722 </span>  memory-should-contain [
<span id="L1723" class="LineNr">1723 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1724" class="LineNr">1724 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1725" class="LineNr">1725 </span>  ]
<span id="L1726" class="LineNr">1726 </span>  <span class="Comment"># undo deletes</span>
<span id="L1727" class="LineNr">1727 </span>  assume-console [
<span id="L1728" class="LineNr">1728 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L1729" class="LineNr">1729 </span>  ]
<span id="L1730" class="LineNr">1730 </span>  run [
<span id="L1731" class="LineNr">1731 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1732" class="LineNr">1732 </span>  ]
<span id="L1733" class="LineNr">1733 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1734" class="LineNr">1734 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1735" class="LineNr">1735 </span>  memory-should-contain [
<span id="L1736" class="LineNr">1736 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1737" class="LineNr">1737 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1738" class="LineNr">1738 </span>  ]
<span id="L1739" class="LineNr">1739 </span>  screen-should-contain [
<span id="L1740" class="LineNr">1740 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1741" class="LineNr">1741 </span>  <span class="Conceal">¦</span><span class="Constant"> .adef      .</span>
<span id="L1742" class="LineNr">1742 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1743" class="LineNr">1743 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1744" class="LineNr">1744 </span>  ]
<span id="L1745" class="LineNr">1745 </span>  <span class="Comment"># undo backspace</span>
<span id="L1746" class="LineNr">1746 </span>  assume-console [
<span id="L1747" class="LineNr">1747 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L1748" class="LineNr">1748 </span>  ]
<span id="L1749" class="LineNr">1749 </span>  run [
<span id="L1750" class="LineNr">1750 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1751" class="LineNr">1751 </span>  ]
<span id="L1752" class="LineNr">1752 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1753" class="LineNr">1753 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1754" class="LineNr">1754 </span>  memory-should-contain [
<span id="L1755" class="LineNr">1755 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1756" class="LineNr">1756 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1757" class="LineNr">1757 </span>  ]
<span id="L1758" class="LineNr">1758 </span>  screen-should-contain [
<span id="L1759" class="LineNr">1759 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1760" class="LineNr">1760 </span>  <span class="Conceal">¦</span><span class="Constant"> .abdef     .</span>
<span id="L1761" class="LineNr">1761 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1762" class="LineNr">1762 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1763" class="LineNr">1763 </span>  ]
<span id="L1764" class="LineNr">1764 </span>  <span class="Comment"># undo first delete</span>
<span id="L1765" class="LineNr">1765 </span>  assume-console [
<span id="L1766" class="LineNr">1766 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L1767" class="LineNr">1767 </span>  ]
<span id="L1768" class="LineNr">1768 </span>  run [
<span id="L1769" class="LineNr">1769 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1770" class="LineNr">1770 </span>  ]
<span id="L1771" class="LineNr">1771 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1772" class="LineNr">1772 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1773" class="LineNr">1773 </span>  memory-should-contain [
<span id="L1774" class="LineNr">1774 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1775" class="LineNr">1775 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1776" class="LineNr">1776 </span>  ]
<span id="L1777" class="LineNr">1777 </span>  screen-should-contain [
<span id="L1778" class="LineNr">1778 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1779" class="LineNr">1779 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcdef    .</span>
<span id="L1780" class="LineNr">1780 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1781" class="LineNr">1781 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1782" class="LineNr">1782 </span>  ]
<span id="L1783" class="LineNr">1783 </span>  <span class="Comment"># redo first delete</span>
<span id="L1784" class="LineNr">1784 </span>  assume-console [
<span id="L1785" class="LineNr">1785 </span>  <span class="Conceal">¦</span> press ctrl-y
<span id="L1786" class="LineNr">1786 </span>  ]
<span id="L1787" class="LineNr">1787 </span>  run [
<span id="L1788" class="LineNr">1788 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1789" class="LineNr">1789 </span>  ]
<span id="L1790" class="LineNr">1790 </span>  <span class="Comment"># first line inserted</span>
<span id="L1791" class="LineNr">1791 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1792" class="LineNr">1792 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1793" class="LineNr">1793 </span>  memory-should-contain [
<span id="L1794" class="LineNr">1794 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1795" class="LineNr">1795 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1796" class="LineNr">1796 </span>  ]
<span id="L1797" class="LineNr">1797 </span>  screen-should-contain [
<span id="L1798" class="LineNr">1798 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1799" class="LineNr">1799 </span>  <span class="Conceal">¦</span><span class="Constant"> .abdef     .</span>
<span id="L1800" class="LineNr">1800 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1801" class="LineNr">1801 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1802" class="LineNr">1802 </span>  ]
<span id="L1803" class="LineNr">1803 </span>  <span class="Comment"># redo backspace</span>
<span id="L1804" class="LineNr">1804 </span>  assume-console [
<span id="L1805" class="LineNr">1805 </span>  <span class="Conceal">¦</span> press ctrl-y
<span id="L1806" class="LineNr">1806 </span>  ]
<span id="L1807" class="LineNr">1807 </span>  run [
<span id="L1808" class="LineNr">1808 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1809" class="LineNr">1809 </span>  ]
<span id="L1810" class="LineNr">1810 </span>  <span class="Comment"># first line inserted</span>
<span id="L1811" class="LineNr">1811 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1812" class="LineNr">1812 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1813" class="LineNr">1813 </span>  memory-should-contain [
<span id="L1814" class="LineNr">1814 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1815" class="LineNr">1815 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1816" class="LineNr">1816 </span>  ]
<span id="L1817" class="LineNr">1817 </span>  screen-should-contain [
<span id="L1818" class="LineNr">1818 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1819" class="LineNr">1819 </span>  <span class="Conceal">¦</span><span class="Constant"> .adef      .</span>
<span id="L1820" class="LineNr">1820 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1821" class="LineNr">1821 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1822" class="LineNr">1822 </span>  ]
<span id="L1823" class="LineNr">1823 </span>  <span class="Comment"># redo deletes</span>
<span id="L1824" class="LineNr">1824 </span>  assume-console [
<span id="L1825" class="LineNr">1825 </span>  <span class="Conceal">¦</span> press ctrl-y
<span id="L1826" class="LineNr">1826 </span>  ]
<span id="L1827" class="LineNr">1827 </span>  run [
<span id="L1828" class="LineNr">1828 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1829" class="LineNr">1829 </span>  ]
<span id="L1830" class="LineNr">1830 </span>  <span class="Comment"># first line inserted</span>
<span id="L1831" class="LineNr">1831 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1832" class="LineNr">1832 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1833" class="LineNr">1833 </span>  memory-should-contain [
<span id="L1834" class="LineNr">1834 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1835" class="LineNr">1835 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1836" class="LineNr">1836 </span>  ]
<span id="L1837" class="LineNr">1837 </span>  screen-should-contain [
<span id="L1838" class="LineNr">1838 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1839" class="LineNr">1839 </span>  <span class="Conceal">¦</span><span class="Constant"> .af        .</span>
<span id="L1840" class="LineNr">1840 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1841" class="LineNr">1841 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1842" class="LineNr">1842 </span>  ]
<span id="L1843" class="LineNr">1843 </span>]
<span id="L1844" class="LineNr">1844 </span>
<span id="L1845" class="LineNr">1845 </span><span class="muRecipe">after</span> <span class="Constant"><a href='003-shortcuts.mu.html#L366'>&lt;begin-delete-character&gt;</a></span> [
<span id="L1846" class="LineNr">1846 </span>  top-before:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L1847" class="LineNr">1847 </span>]
<span id="L1848" class="LineNr">1848 </span><span class="muRecipe">before</span> <span class="Constant"><a href='003-shortcuts.mu.html#L368'>&lt;end-delete-character&gt;</a></span> [
<span id="L1849" class="LineNr">1849 </span>  <span class="Delimiter">{</span>
<span id="L1850" class="LineNr">1850 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> deleted-cell  <span class="Comment"># delete failed; don't add an undo operation</span>
<span id="L1851" class="LineNr">1851 </span>  <span class="Conceal">¦</span> top-after:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L1852" class="LineNr">1852 </span>  <span class="Conceal">¦</span> cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L1853" class="LineNr">1853 </span>  <span class="Conceal">¦</span> cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L1854" class="LineNr">1854 </span>  <span class="Conceal">¦</span> before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L1855" class="LineNr">1855 </span>  <span class="Conceal">¦</span> undo:&amp;:<a href='../064list.mu.html#L6'>list</a>:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
<span id="L1856" class="LineNr">1856 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
<span id="L1857" class="LineNr">1857 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># if previous operation was an insert, coalesce this operation with it</span>
<span id="L1858" class="LineNr">1858 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> undo
<span id="L1859" class="LineNr">1859 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first undo
<span id="L1860" class="LineNr">1860 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion:<a href='012-editor-undo.mu.html#L43'>delete-operation</a>, is-delete?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">delete:variant</span>
<span id="L1861" class="LineNr">1861 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-delete?
<span id="L1862" class="LineNr">1862 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> previous-coalesce-tag:num <span class="Special">&lt;-</span> get deletion, <span class="Constant">tag:offset</span>
<span id="L1863" class="LineNr">1863 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> coalesce?:bool <span class="Special">&lt;-</span> equal previous-coalesce-tag, <span class="Constant">2/coalesce-delete</span>
<span id="L1864" class="LineNr">1864 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> coalesce?
<span id="L1865" class="LineNr">1865 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> delete-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
<span id="L1866" class="LineNr">1866 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">delete-until:offset</span>, delete-until
<span id="L1867" class="LineNr">1867 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deleted-so-far:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">deleted-text:offset</span>
<span id="L1868" class="LineNr">1868 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deleted-so-far <span class="Special">&lt;-</span> append deleted-so-far, deleted-cell
<span id="L1869" class="LineNr">1869 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">deleted-text:offset</span>, deleted-so-far
<span id="L1870" class="LineNr">1870 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-row:offset</span>, cursor-row
<span id="L1871" class="LineNr">1871 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-column:offset</span>, cursor-column
<span id="L1872" class="LineNr">1872 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-top-of-screen:offset</span>, top-after
<span id="L1873" class="LineNr">1873 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, deletion
<span id="L1874" class="LineNr">1874 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break</span> <span class="Constant">+done-adding-delete-operation</span>
<span id="L1875" class="LineNr">1875 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
<span id="L1876" class="LineNr">1876 </span>  <span class="Conceal">¦</span> <span class="Comment"># if not, create a new operation</span>
<span id="L1877" class="LineNr">1877 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
<span id="L1878" class="LineNr">1878 </span>  <span class="Conceal">¦</span> deleted-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
<span id="L1879" class="LineNr">1879 </span>  <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, save-row/before, save-column/before, top-before, cursor-row/after, cursor-column/after, top-after, deleted-cell/deleted, before-cursor/delete-from, deleted-until, <span class="Constant">2/coalesce-delete</span>
<span id="L1880" class="LineNr">1880 </span>  <span class="Conceal">¦</span> editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L202'>add-operation</a> editor, op
<span id="L1881" class="LineNr">1881 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> +done-adding-delete-operation</span>
<span id="L1882" class="LineNr">1882 </span>  <span class="Delimiter">}</span>
<span id="L1883" class="LineNr">1883 </span>]
<span id="L1884" class="LineNr">1884 </span>
<span id="L1885" class="LineNr">1885 </span><span class="Comment"># undo ctrl-k</span>
<span id="L1886" class="LineNr">1886 </span>
<span id="L1887" class="LineNr">1887 </span><span class="muScenario">scenario</span> editor-can-undo-and-redo-ctrl-k [
<span id="L1888" class="LineNr">1888 </span>  <span class="Constant">local-scope</span>
<span id="L1889" class="LineNr">1889 </span>  <span class="Comment"># create an editor</span>
<span id="L1890" class="LineNr">1890 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1891" class="LineNr">1891 </span>  contents:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L1892" class="LineNr">1892 </span><span class="Constant">def]</span>
<span id="L1893" class="LineNr">1893 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1894" class="LineNr">1894 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1895" class="LineNr">1895 </span>  <span class="Comment"># insert some text and hit delete and backspace a few times</span>
<span id="L1896" class="LineNr">1896 </span>  assume-console [
<span id="L1897" class="LineNr">1897 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
<span id="L1898" class="LineNr">1898 </span>  <span class="Conceal">¦</span> press ctrl-k
<span id="L1899" class="LineNr">1899 </span>  ]
<span id="L1900" class="LineNr">1900 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1901" class="LineNr">1901 </span>  screen-should-contain [
<span id="L1902" class="LineNr">1902 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1903" class="LineNr">1903 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
<span id="L1904" class="LineNr">1904 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
<span id="L1905" class="LineNr">1905 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1906" class="LineNr">1906 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1907" class="LineNr">1907 </span>  ]
<span id="L1908" class="LineNr">1908 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1909" class="LineNr">1909 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1910" class="LineNr">1910 </span>  memory-should-contain [
<span id="L1911" class="LineNr">1911 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1912" class="LineNr">1912 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1913" class="LineNr">1913 </span>  ]
<span id="L1914" class="LineNr">1914 </span>  <span class="Comment"># undo</span>
<span id="L1915" class="LineNr">1915 </span>  assume-console [
<span id="L1916" class="LineNr">1916 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L1917" class="LineNr">1917 </span>  ]
<span id="L1918" class="LineNr">1918 </span>  run [
<span id="L1919" class="LineNr">1919 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1920" class="LineNr">1920 </span>  ]
<span id="L1921" class="LineNr">1921 </span>  screen-should-contain [
<span id="L1922" class="LineNr">1922 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1923" class="LineNr">1923 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
<span id="L1924" class="LineNr">1924 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
<span id="L1925" class="LineNr">1925 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1926" class="LineNr">1926 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1927" class="LineNr">1927 </span>  ]
<span id="L1928" class="LineNr">1928 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1929" class="LineNr">1929 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1930" class="LineNr">1930 </span>  memory-should-contain [
<span id="L1931" class="LineNr">1931 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1932" class="LineNr">1932 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1933" class="LineNr">1933 </span>  ]
<span id="L1934" class="LineNr">1934 </span>  <span class="Comment"># redo</span>
<span id="L1935" class="LineNr">1935 </span>  assume-console [
<span id="L1936" class="LineNr">1936 </span>  <span class="Conceal">¦</span> press ctrl-y
<span id="L1937" class="LineNr">1937 </span>  ]
<span id="L1938" class="LineNr">1938 </span>  run [
<span id="L1939" class="LineNr">1939 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1940" class="LineNr">1940 </span>  ]
<span id="L1941" class="LineNr">1941 </span>  <span class="Comment"># first line inserted</span>
<span id="L1942" class="LineNr">1942 </span>  screen-should-contain [
<span id="L1943" class="LineNr">1943 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1944" class="LineNr">1944 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
<span id="L1945" class="LineNr">1945 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
<span id="L1946" class="LineNr">1946 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1947" class="LineNr">1947 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1948" class="LineNr">1948 </span>  ]
<span id="L1949" class="LineNr">1949 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1950" class="LineNr">1950 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1951" class="LineNr">1951 </span>  memory-should-contain [
<span id="L1952" class="LineNr">1952 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1953" class="LineNr">1953 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1954" class="LineNr">1954 </span>  ]
<span id="L1955" class="LineNr">1955 </span>  <span class="Comment"># cursor should be in the right place</span>
<span id="L1956" class="LineNr">1956 </span>  assume-console [
<span id="L1957" class="LineNr">1957 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
<span id="L1958" class="LineNr">1958 </span>  ]
<span id="L1959" class="LineNr">1959 </span>  run [
<span id="L1960" class="LineNr">1960 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1961" class="LineNr">1961 </span>  ]
<span id="L1962" class="LineNr">1962 </span>  screen-should-contain [
<span id="L1963" class="LineNr">1963 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1964" class="LineNr">1964 </span>  <span class="Conceal">¦</span><span class="Constant"> .a1        .</span>
<span id="L1965" class="LineNr">1965 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
<span id="L1966" class="LineNr">1966 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1967" class="LineNr">1967 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L1968" class="LineNr">1968 </span>  ]
<span id="L1969" class="LineNr">1969 </span>]
<span id="L1970" class="LineNr">1970 </span>
<span id="L1971" class="LineNr">1971 </span><span class="muRecipe">after</span> <span class="Constant"><a href='003-shortcuts.mu.html#L2540'>&lt;begin-delete-to-end-of-line&gt;</a></span> [
<span id="L1972" class="LineNr">1972 </span>  top-before:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L1973" class="LineNr">1973 </span>]
<span id="L1974" class="LineNr">1974 </span><span class="muRecipe">before</span> <span class="Constant"><a href='003-shortcuts.mu.html#L2542'>&lt;end-delete-to-end-of-line&gt;</a></span> [
<span id="L1975" class="LineNr">1975 </span>  <span class="Delimiter">{</span>
<span id="L1976" class="LineNr">1976 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> deleted-cells  <span class="Comment"># delete failed; don't add an undo operation</span>
<span id="L1977" class="LineNr">1977 </span>  <span class="Conceal">¦</span> top-after:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L1978" class="LineNr">1978 </span>  <span class="Conceal">¦</span> cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L1979" class="LineNr">1979 </span>  <span class="Conceal">¦</span> cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L1980" class="LineNr">1980 </span>  <span class="Conceal">¦</span> deleted-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
<span id="L1981" class="LineNr">1981 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
<span id="L1982" class="LineNr">1982 </span>  <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, save-row/before, save-column/before, top-before, cursor-row/after, cursor-column/after, top-after, deleted-cells/deleted, before-cursor/delete-from, deleted-until, <span class="Constant">0/never-coalesce</span>
<span id="L1983" class="LineNr">1983 </span>  <span class="Conceal">¦</span> editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L202'>add-operation</a> editor, op
<span id="L1984" class="LineNr">1984 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> +done-adding-delete-operation</span>
<span id="L1985" class="LineNr">1985 </span>  <span class="Delimiter">}</span>
<span id="L1986" class="LineNr">1986 </span>]
<span id="L1987" class="LineNr">1987 </span>
<span id="L1988" class="LineNr">1988 </span><span class="Comment"># undo ctrl-u</span>
<span id="L1989" class="LineNr">1989 </span>
<span id="L1990" class="LineNr">1990 </span><span class="muScenario">scenario</span> editor-can-undo-and-redo-ctrl-u [
<span id="L1991" class="LineNr">1991 </span>  <span class="Constant">local-scope</span>
<span id="L1992" class="LineNr">1992 </span>  <span class="Comment"># create an editor</span>
<span id="L1993" class="LineNr">1993 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1994" class="LineNr">1994 </span>  contents:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L1995" class="LineNr">1995 </span><span class="Constant">def]</span>
<span id="L1996" class="LineNr">1996 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1997" class="LineNr">1997 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1998" class="LineNr">1998 </span>  <span class="Comment"># insert some text and hit delete and backspace a few times</span>
<span id="L1999" class="LineNr">1999 </span>  assume-console [
<span id="L2000" class="LineNr">2000 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
<span id="L2001" class="LineNr">2001 </span>  <span class="Conceal">¦</span> press ctrl-u
<span id="L2002" class="LineNr">2002 </span>  ]
<span id="L2003" class="LineNr">2003 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2004" class="LineNr">2004 </span>  screen-should-contain [
<span id="L2005" class="LineNr">2005 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L2006" class="LineNr">2006 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
<span id="L2007" class="LineNr">2007 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
<span id="L2008" class="LineNr">2008 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2009" class="LineNr">2009 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L2010" class="LineNr">2010 </span>  ]
<span id="L2011" class="LineNr">2011 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L2012" class="LineNr">2012 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L2013" class="LineNr">2013 </span>  memory-should-contain [
<span id="L2014" class="LineNr">2014 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L2015" class="LineNr">2015 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L2016" class="LineNr">2016 </span>  ]
<span id="L2017" class="LineNr">2017 </span>  <span class="Comment"># undo</span>
<span id="L2018" class="LineNr">2018 </span>  assume-console [
<span id="L2019" class="LineNr">2019 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L2020" class="LineNr">2020 </span>  ]
<span id="L2021" class="LineNr">2021 </span>  run [
<span id="L2022" class="LineNr">2022 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2023" class="LineNr">2023 </span>  ]
<span id="L2024" class="LineNr">2024 </span>  screen-should-contain [
<span id="L2025" class="LineNr">2025 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L2026" class="LineNr">2026 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
<span id="L2027" class="LineNr">2027 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
<span id="L2028" class="LineNr">2028 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2029" class="LineNr">2029 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L2030" class="LineNr">2030 </span>  ]
<span id="L2031" class="LineNr">2031 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L2032" class="LineNr">2032 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L2033" class="LineNr">2033 </span>  memory-should-contain [
<span id="L2034" class="LineNr">2034 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L2035" class="LineNr">2035 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L2036" class="LineNr">2036 </span>  ]
<span id="L2037" class="LineNr">2037 </span>  <span class="Comment"># redo</span>
<span id="L2038" class="LineNr">2038 </span>  assume-console [
<span id="L2039" class="LineNr">2039 </span>  <span class="Conceal">¦</span> press ctrl-y
<span id="L2040" class="LineNr">2040 </span>  ]
<span id="L2041" class="LineNr">2041 </span>  run [
<span id="L2042" class="LineNr">2042 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2043" class="LineNr">2043 </span>  ]
<span id="L2044" class="LineNr">2044 </span>  <span class="Comment"># first line inserted</span>
<span id="L2045" class="LineNr">2045 </span>  screen-should-contain [
<span id="L2046" class="LineNr">2046 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L2047" class="LineNr">2047 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
<span id="L2048" class="LineNr">2048 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
<span id="L2049" class="LineNr">2049 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2050" class="LineNr">2050 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L2051" class="LineNr">2051 </span>  ]
<span id="L2052" class="LineNr">2052 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L2053" class="LineNr">2053 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L2054" class="LineNr">2054 </span>  memory-should-contain [
<span id="L2055" class="LineNr">2055 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L2056" class="LineNr">2056 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L2057" class="LineNr">2057 </span>  ]
<span id="L2058" class="LineNr">2058 </span>  <span class="Comment"># cursor should be in the right place</span>
<span id="L2059" class="LineNr">2059 </span>  assume-console [
<span id="L2060" class="LineNr">2060 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
<span id="L2061" class="LineNr">2061 </span>  ]
<span id="L2062" class="LineNr">2062 </span>  run [
<span id="L2063" class="LineNr">2063 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2064" class="LineNr">2064 </span>  ]
<span id="L2065" class="LineNr">2065 </span>  screen-should-contain [
<span id="L2066" class="LineNr">2066 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L2067" class="LineNr">2067 </span>  <span class="Conceal">¦</span><span class="Constant"> .1c        .</span>
<span id="L2068" class="LineNr">2068 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
<span id="L2069" class="LineNr">2069 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2070" class="LineNr">2070 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L2071" class="LineNr">2071 </span>  ]
<span id="L2072" class="LineNr">2072 </span>]
<span id="L2073" class="LineNr">2073 </span>
<span id="L2074" class="LineNr">2074 </span><span class="muRecipe">after</span> <span class="Constant"><a href='003-shortcuts.mu.html#L1963'>&lt;begin-delete-to-start-of-line&gt;</a></span> [
<span id="L2075" class="LineNr">2075 </span>  top-before:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L2076" class="LineNr">2076 </span>]
<span id="L2077" class="LineNr">2077 </span><span class="muRecipe">before</span> <span class="Constant"><a href='003-shortcuts.mu.html#L1965'>&lt;end-delete-to-start-of-line&gt;</a></span> [
<span id="L2078" class="LineNr">2078 </span>  <span class="Delimiter">{</span>
<span id="L2079" class="LineNr">2079 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> deleted-cells  <span class="Comment"># delete failed; don't add an undo operation</span>
<span id="L2080" class="LineNr">2080 </span>  <span class="Conceal">¦</span> top-after:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L2081" class="LineNr">2081 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
<span id="L2082" class="LineNr">2082 </span>  <span class="Conceal">¦</span> before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L2083" class="LineNr">2083 </span>  <span class="Conceal">¦</span> deleted-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
<span id="L2084" class="LineNr">2084 </span>  <span class="Conceal">¦</span> cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L2085" class="LineNr">2085 </span>  <span class="Conceal">¦</span> cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L2086" class="LineNr">2086 </span>  <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, save-row/before, save-column/before, top-before, cursor-row/after, cursor-column/after, top-after, deleted-cells/deleted, before-cursor/delete-from, deleted-until, <span class="Constant">0/never-coalesce</span>
<span id="L2087" class="LineNr">2087 </span>  <span class="Conceal">¦</span> editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L202'>add-operation</a> editor, op
<span id="L2088" class="LineNr">2088 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> +done-adding-delete-operation</span>
<span id="L2089" class="LineNr">2089 </span>  <span class="Delimiter">}</span>
<span id="L2090" class="LineNr">2090 </span>]
<span id="L2091" class="LineNr">2091 </span>
<span id="L2092" class="LineNr">2092 </span><span class="muScenario">scenario</span> editor-can-undo-and-redo-ctrl-u-2 [
<span id="L2093" class="LineNr">2093 </span>  <span class="Constant">local-scope</span>
<span id="L2094" class="LineNr">2094 </span>  <span class="Comment"># create an editor</span>
<span id="L2095" class="LineNr">2095 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2096" class="LineNr">2096 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2097" class="LineNr">2097 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2098" class="LineNr">2098 </span>  <span class="Comment"># insert some text and hit delete and backspace a few times</span>
<span id="L2099" class="LineNr">2099 </span>  assume-console [
<span id="L2100" class="LineNr">2100 </span>  <span class="Conceal">¦</span> type <span class="Constant">[abc]</span>
<span id="L2101" class="LineNr">2101 </span>  <span class="Conceal">¦</span> press ctrl-u
<span id="L2102" class="LineNr">2102 </span>  <span class="Conceal">¦</span> press ctrl-z
<span id="L2103" class="LineNr">2103 </span>  ]
<span id="L2104" class="LineNr">2104 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2105" class="LineNr">2105 </span>  screen-should-contain [
<span id="L2106" class="LineNr">2106 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L2107" class="LineNr">2107 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
<span id="L2108" class="LineNr">2108 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2109" class="LineNr">2109 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
<span id="L2110" class="LineNr">2110 </span>  ]
<span id="L2111" class="LineNr">2111 </span>]
</pre>
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