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-rw-r--r--README.md46
-rw-r--r--app.lua4
-rw-r--r--conf.lua3
-rw-r--r--drawing.lua6
-rw-r--r--edit.lua80
-rw-r--r--keychord.lua4
-rw-r--r--log.lua50
-rw-r--r--log_browser.lua6
-rw-r--r--main.lua28
-rw-r--r--run.lua20
-rw-r--r--run_tests.lua29
-rw-r--r--select.lua54
-rw-r--r--source.lua30
-rw-r--r--source_edit.lua26
-rw-r--r--source_text.lua2
-rw-r--r--source_undo.lua8
-rw-r--r--text.lua137
-rw-r--r--text_tests.lua622
-rw-r--r--undo.lua88
19 files changed, 138 insertions, 1105 deletions
diff --git a/README.md b/README.md
index 0887f4a..bb4ab40 100644
--- a/README.md
+++ b/README.md
@@ -1,10 +1,10 @@
-# An editor for plain text.
+# A read-only viewer for plain text.
 
 [![0 dependencies!](https://0dependencies.dev/0dependencies.svg)](https://0dependencies.dev)
 
 Not very useful by itself, but it's a fork of [lines.love](http://akkartik.name/lines.html)
-that you can take in other directions besides line drawings, while easily
-sharing patches between forks.
+that you can take in other directions, while easily sharing patches between
+forks.
 
 Designed above all to be easy to modify and give you early warning if your
 modifications break something.
@@ -19,7 +19,7 @@ optionally with a file path to edit.
 
 Alternatively, turn it into a .love file you can double-click on:
 ```
-$ zip -r /tmp/text.love *.lua
+$ zip -r /tmp/view.love *.lua
 ```
 
 By default, it reads/writes the file `lines.txt` in
@@ -56,33 +56,23 @@ found anything amiss: http://akkartik.name/contact
 
 This repo is a fork of [lines.love](http://akkartik.name/lines.html), an
 editor for plain text where you can also seamlessly insert line drawings.
-Updates to it can be downloaded from the following mirrors:
-
-* https://repo.or.cz/text.love.git
-* https://tildegit.org/akkartik/text.love
-* https://git.tilde.institute/akkartik/text.love
-* https://git.merveilles.town/akkartik/text.love
-* https://git.sr.ht/~akkartik/text.love
-* https://github.com/akkartik/text.love
-* https://codeberg.org/akkartik/text.love
-* https://notabug.org/akkartik/text.love
-* https://pagure.io/text.love
-* https://nest.pijul.com/akkartik/text.love (using the Pijul version control system)
+Its immediate upstream is [text.love](https://git.sr.ht/~akkartik/text.love),
+a version without support for line drawings. Updates to it can be downloaded
+from the following mirrors:
+
+* https://git.sr.ht/~akkartik/view.love
+* https://repo.or.cz/view.love.git
+* https://tildegit.org/akkartik/view.love
+* https://git.tilde.institute/akkartik/view.love
+* https://git.merveilles.town/akkartik/view.love
+* https://github.com/akkartik/view.love
+* https://codeberg.org/akkartik/view.love
+* https://notabug.org/akkartik/view.love
+* https://pagure.io/view.love
+* https://nest.pijul.com/akkartik/view.love (using the Pijul version control system)
 
 Further forks are encouraged. If you show me your fork, I'll link to it here.
 
-* https://git.sr.ht/~akkartik/view.love -- a stripped down version without
-  support for modifying files; useful starting point for some forks.
-* https://git.sr.ht/~akkartik/pong.love -- a fairly minimal example app that
-  can edit and debug its own source code.
-* https://git.sr.ht/~akkartik/template-live-editor -- a template for
-  building "free-wheeling" live programs (easy to fork, can be modified as
-  they run), with a text editor primitive.
-* https://git.sr.ht/~akkartik/luaML.love -- a free-wheeling 'browser' for a
-  Lua-based markup language built as a live program.
-* https://git.sr.ht/~akkartik/driver.love -- a programming environment for
-  modifying free-wheeling programs while they run.
-
 ## Feedback
 
 [Most appreciated.](http://akkartik.name/contact) Messages, PRs, patches,
diff --git a/app.lua b/app.lua
index 1bec1f0..2375ff9 100644
--- a/app.lua
+++ b/app.lua
@@ -428,9 +428,9 @@ function App.disable_tests()
       -- love.keyboard.isDown doesn't work on Android, so emulate it using
       -- keypressed and keyreleased events
       if name == 'keypressed' then
-        love.handlers[name] = function(key, scancode, isrepeat)
+        love.handlers[name] = function(key, scancode, is_repeat)
                                 Keys_down[key] = true
-                                return App.keypressed(key, scancode, isrepeat)
+                                return App.keypressed(key, scancode, is_repeat)
                               end
       elseif name == 'keyreleased' then
         love.handlers[name] = function(key, scancode)
diff --git a/conf.lua b/conf.lua
new file mode 100644
index 0000000..d5b3903
--- /dev/null
+++ b/conf.lua
@@ -0,0 +1,3 @@
+function love.conf(t)
+  t.identity = 'view'
+end
diff --git a/drawing.lua b/drawing.lua
index 92e3d5f..b74855a 100644
--- a/drawing.lua
+++ b/drawing.lua
@@ -221,7 +221,7 @@ function Drawing.in_drawing(State, line_index, x,y, left,right)
   return y >= starty and y < starty + Drawing.pixels(drawing.h, width) and x >= left and x < right
 end
 
-function Drawing.mouse_press(State, drawing_index, x,y, mouse_button)
+function Drawing.mouse_press(State, drawing_index, x,y, mouse_button, is_touch, presses)
   local drawing = State.lines[drawing_index]
   local starty = Text.starty(State, drawing_index)
   local cx = Drawing.coord(x-State.left, State.width)
@@ -300,7 +300,7 @@ function Drawing.relax_constraints(drawing, p)
   end
 end
 
-function Drawing.mouse_release(State, x,y, mouse_button)
+function Drawing.mouse_release(State, x,y, mouse_button, is_touch, presses)
   if State.current_drawing_mode == 'move' then
     State.current_drawing_mode = State.previous_drawing_mode
     State.previous_drawing_mode = nil
@@ -396,7 +396,7 @@ function Drawing.mouse_release(State, x,y, mouse_button)
   end
 end
 
-function Drawing.keychord_press(State, chord)
+function Drawing.keychord_press(State, chord, key, scancode, is_repeat)
   if chord == 'C-p' and not App.mouse_down(1) then
     State.current_drawing_mode = 'freehand'
   elseif App.mouse_down(1) and chord == 'l' then
diff --git a/edit.lua b/edit.lua
index 97860b7..54b8aa9 100644
--- a/edit.lua
+++ b/edit.lua
@@ -56,11 +56,6 @@ function edit.initialize_state(top, left, right, font, font_height, line_height)
     width = right-left,
 
     filename = love.filesystem.getSourceBaseDirectory()..'/lines.txt',  -- '/' should work even on Windows
-    next_save = nil,
-
-    -- undo
-    history = {},
-    next_history = 1,
 
     -- search
     search_term = nil,
@@ -124,28 +119,12 @@ function edit.draw(State)
 end
 
 function edit.update(State, dt)
-  if State.next_save and State.next_save < Current_time then
-    save_to_disk(State)
-    State.next_save = nil
-  end
-end
-
-function schedule_save(State)
-  if State.next_save == nil then
-    State.next_save = Current_time + 3  -- short enough that you're likely to still remember what you did
-  end
 end
 
 function edit.quit(State)
-  -- make sure to save before quitting
-  if State.next_save then
-    save_to_disk(State)
-    -- give some time for the OS to flush everything to disk
-    love.timer.sleep(0.1)
-  end
 end
 
-function edit.mouse_press(State, x,y, mouse_button)
+function edit.mouse_press(State, x,y, mouse_button, is_touch, presses)
   if State.search_term then return end
   State.mouse_down = mouse_button
 --?   print_and_log(('edit.mouse_press: cursor at %d,%d'):format(State.cursor1.line, State.cursor1.pos))
@@ -190,7 +169,7 @@ function edit.mouse_press(State, x,y, mouse_button)
   State.selection1 = Text.final_loc_on_screen(State)
 end
 
-function edit.mouse_release(State, x,y, mouse_button)
+function edit.mouse_release(State, x,y, mouse_button, is_touch, presses)
   if State.search_term then return end
 --?   print_and_log(('edit.mouse_release(%d,%d): cursor at %d,%d'):format(x,y, State.cursor1.line, State.cursor1.pos))
   State.mouse_down = nil
@@ -251,13 +230,10 @@ function edit.text_input(State, t)
   if State.search_term then
     State.search_term = State.search_term..t
     Text.search_next(State)
-  else
-    Text.text_input(State, t)
   end
-  schedule_save(State)
 end
 
-function edit.keychord_press(State, chord, key)
+function edit.keychord_press(State, chord, key, scancode, is_repeat)
   if State.selection1.line and
       -- printable character created using shift key => delete selection
       -- (we're not creating any ctrl-shift- or alt-shift- combinations using regular/printable keys)
@@ -309,29 +285,6 @@ function edit.keychord_press(State, chord, key)
   elseif chord == 'C-0' then
     edit.update_font_settings(State, 20)
     Text.redraw_all(State)
-  -- undo
-  elseif chord == 'C-z' then
-    local event = undo_event(State)
-    if event then
-      local src = event.before
-      State.screen_top1 = deepcopy(src.screen_top)
-      State.cursor1 = deepcopy(src.cursor)
-      State.selection1 = deepcopy(src.selection)
-      patch(State.lines, event.after, event.before)
-      Text.redraw_all(State)  -- if we're scrolling, reclaim all line caches to avoid memory leaks
-      schedule_save(State)
-    end
-  elseif chord == 'C-y' then
-    local event = redo_event(State)
-    if event then
-      local src = event.after
-      State.screen_top1 = deepcopy(src.screen_top)
-      State.cursor1 = deepcopy(src.cursor)
-      State.selection1 = deepcopy(src.selection)
-      patch(State.lines, event.before, event.after)
-      Text.redraw_all(State)  -- if we're scrolling, reclaim all line caches to avoid memory leaks
-      schedule_save(State)
-    end
   -- clipboard
   elseif chord == 'C-a' then
     State.selection1 = {line=1, pos=1}
@@ -341,33 +294,8 @@ function edit.keychord_press(State, chord, key)
     if s then
       App.set_clipboard(s)
     end
-  elseif chord == 'C-x' then
-    local s = Text.cut_selection_and_record_undo_event(State)
-    if s then
-      App.set_clipboard(s)
-    end
-    schedule_save(State)
-  elseif chord == 'C-v' then
-    -- We don't have a good sense of when to scroll, so we'll be conservative
-    -- and sometimes scroll when we didn't quite need to.
-    local before_line = State.cursor1.line
-    local before = snapshot(State, before_line)
-    local clipboard_data = App.get_clipboard()
-    for _,code in utf8.codes(clipboard_data) do
-      local c = utf8.char(code)
-      if c == '\n' then
-        Text.insert_return(State)
-      else
-        Text.insert_at_cursor(State, c)
-      end
-    end
-    if Text.cursor_out_of_screen(State) then
-      Text.snap_cursor_to_bottom_of_screen(State, State.left, State.right)
-    end
-    record_undo_event(State, {before=before, after=snapshot(State, before_line, State.cursor1.line)})
-    schedule_save(State)
   else
-    Text.keychord_press(State, chord)
+    Text.keychord_press(State, chord, key, scancode, is_repeat)
   end
 end
 
diff --git a/keychord.lua b/keychord.lua
index f1b6a59..5de899d 100644
--- a/keychord.lua
+++ b/keychord.lua
@@ -2,13 +2,13 @@
 
 Modifiers = {'lctrl', 'rctrl', 'lalt', 'ralt', 'lshift', 'rshift', 'lgui', 'rgui'}
 
-function App.keypressed(key, scancode, isrepeat)
+function App.keypressed(key, scancode, is_repeat)
   if array.find(Modifiers, key) then
     -- do nothing when the modifier is pressed
     return
   end
   -- include the modifier(s) when the non-modifer is pressed
-  App.keychord_press(App.combine_modifiers(key), key)
+  App.keychord_press(App.combine_modifiers(key), key, scancode, is_repeat)
 end
 
 function App.combine_modifiers(key)
diff --git a/log.lua b/log.lua
index 8903e08..4e428d8 100644
--- a/log.lua
+++ b/log.lua
@@ -1,38 +1,38 @@
 function log(stack_frame_index, obj)
-	local info = debug.getinfo(stack_frame_index, 'Sl')
-	local msg
-	if type(obj) == 'string' then
-		msg = obj
-	else
-		msg = json.encode(obj)
-	end
-	love.filesystem.append('log', info.short_src..':'..info.currentline..': '..msg..'\n')
+  local info = debug.getinfo(stack_frame_index, 'Sl')
+  local msg
+  if type(obj) == 'string' then
+    msg = obj
+  else
+    msg = json.encode(obj)
+  end
+  love.filesystem.append('log', info.short_src..':'..info.currentline..': '..msg..'\n')
 end
 
 -- for section delimiters we'll use specific Unicode box characters
 function log_start(name, stack_frame_index)
-	if stack_frame_index == nil then
-		stack_frame_index = 3
-	end
-	-- I'd like to use the unicode character \u{250c} here, but it doesn't work
-	-- in OpenBSD.
-	log(stack_frame_index, '[ u250c ' .. name)
+  if stack_frame_index == nil then
+    stack_frame_index = 3
+  end
+  -- I'd like to use the unicode character \u{250c} here, but it doesn't work
+  -- in OpenBSD.
+  log(stack_frame_index, '[ u250c ' .. name)
 end
 function log_end(name, stack_frame_index)
-	if stack_frame_index == nil then
-		stack_frame_index = 3
-	end
-	-- I'd like to use the unicode character \u{2518} here, but it doesn't work
-	-- in OpenBSD.
-	log(stack_frame_index, '] u2518 ' .. name)
+  if stack_frame_index == nil then
+    stack_frame_index = 3
+  end
+  -- I'd like to use the unicode character \u{2518} here, but it doesn't work
+  -- in OpenBSD.
+  log(stack_frame_index, '] u2518 ' .. name)
 end
 
 function log_new(name, stack_frame_index)
-	if stack_frame_index == nil then
-		stack_frame_index = 4
-	end
-	log_end(name, stack_frame_index)
-	log_start(name, stack_frame_index)
+  if stack_frame_index == nil then
+    stack_frame_index = 4
+  end
+  log_end(name, stack_frame_index)
+  log_start(name, stack_frame_index)
 end
 
 -- rendering graphical objects within sections/boxes
diff --git a/log_browser.lua b/log_browser.lua
index 6e7e6db..fae9d6d 100644
--- a/log_browser.lua
+++ b/log_browser.lua
@@ -183,7 +183,7 @@ end
 function log_browser.quit(State)
 end
 
-function log_browser.mouse_press(State, x,y, mouse_button)
+function log_browser.mouse_press(State, x,y, mouse_button, is_touch, presses)
   local line_index = log_browser.line_index(State, x,y)
   if line_index == nil then
     -- below lower margin
@@ -249,7 +249,7 @@ function log_browser.line_index(State, mx,my)
   end
 end
 
-function log_browser.mouse_release(State, x,y, mouse_button)
+function log_browser.mouse_release(State, x,y, mouse_button, is_touch, presses)
 end
 
 function log_browser.mouse_wheel_move(State, dx,dy)
@@ -267,7 +267,7 @@ end
 function log_browser.text_input(State, t)
 end
 
-function log_browser.keychord_press(State, chord, key)
+function log_browser.keychord_press(State, chord, key, scancode, is_repeat)
   -- move
   if chord == 'up' then
     log_browser.up(State)
diff --git a/main.lua b/main.lua
index e7d35f4..83049c2 100644
--- a/main.lua
+++ b/main.lua
@@ -113,15 +113,15 @@ function check_love_version_for_tests()
   end
 end
 
-function App.initialize(arg)
+function App.initialize(arg, unfiltered_arg)
   love.keyboard.setKeyRepeat(true)
 
   love.graphics.setBackgroundColor(1,1,1)
 
   if Current_app == 'run' then
-    run.initialize(arg)
+    run.initialize(arg, unfiltered_arg)
   elseif Current_app == 'source' then
-    source.initialize(arg)
+    source.initialize(arg, unfiltered_arg)
   elseif current_app_is_warning() then
   else
     assert(false, 'unknown app "'..Current_app..'"')
@@ -207,7 +207,7 @@ function App.update(dt)
   end
 end
 
-function App.keychord_press(chord, key)
+function App.keychord_press(chord, key, scancode, is_repeat)
   -- ignore events for some time after window in focus (mostly alt-tab)
   if Current_time < Last_focus_time + 0.01 then
     return
@@ -251,9 +251,9 @@ function App.keychord_press(chord, key)
     return
   end
   if Current_app == 'run' then
-    if run.keychord_press then run.keychord_press(chord, key) end
+    if run.keychord_press then run.keychord_press(chord, key, scancode, is_repeat) end
   elseif Current_app == 'source' then
-    if source.keychord_press then source.keychord_press(chord, key) end
+    if source.keychord_press then source.keychord_press(chord, key, scancode, is_repeat) end
   else
     assert(false, 'unknown app "'..Current_app..'"')
   end
@@ -293,24 +293,24 @@ function App.keyreleased(key, scancode)
   end
 end
 
-function App.mousepressed(x,y, mouse_button)
+function App.mousepressed(x,y, mouse_button, is_touch, presses)
   if current_app_is_warning() then return end
 --?   print('mouse press', x,y)
   if Current_app == 'run' then
-    if run.mouse_press then run.mouse_press(x,y, mouse_button) end
+    if run.mouse_press then run.mouse_press(x,y, mouse_button, is_touch, presses) end
   elseif Current_app == 'source' then
-    if source.mouse_press then source.mouse_press(x,y, mouse_button) end
+    if source.mouse_press then source.mouse_press(x,y, mouse_button, is_touch, presses) end
   else
     assert(false, 'unknown app "'..Current_app..'"')
   end
 end
 
-function App.mousereleased(x,y, mouse_button)
+function App.mousereleased(x,y, mouse_button, is_touch, presses)
   if current_app_is_warning() then return end
   if Current_app == 'run' then
-    if run.mouse_release then run.mouse_release(x,y, mouse_button) end
+    if run.mouse_release then run.mouse_release(x,y, mouse_button, is_touch, presses) end
   elseif Current_app == 'source' then
-    if source.mouse_release then source.mouse_release(x,y, mouse_button) end
+    if source.mouse_release then source.mouse_release(x,y, mouse_button, is_touch, presses) end
   else
     assert(false, 'unknown app "'..Current_app..'"')
   end
@@ -319,9 +319,9 @@ end
 function App.mousemoved(x,y, dx,dy, is_touch)
   if current_app_is_warning() then return end
   if Current_app == 'run' then
-    if run.mouse_move then run.mouse_move(dx,dy) end
+    if run.mouse_move then run.mouse_move(x,y, dx,dy, is_touch) end
   elseif Current_app == 'source' then
-    if source.mouse_move then source.mouse_move(dx,dy) end
+    if source.mouse_move then source.mouse_move(x,y, dx,dy, is_touch) end
   else
     assert(false, 'unknown app "'..Current_app..'"')
   end
diff --git a/run.lua b/run.lua
index 9a7051d..e317733 100644
--- a/run.lua
+++ b/run.lua
@@ -11,7 +11,7 @@ function run.initialize_globals()
 end
 
 -- called only for real run
-function run.initialize(arg)
+function run.initialize(arg, unfiltered_arg)
   log_new('run')
   if Settings then
     run.load_settings()
@@ -34,7 +34,7 @@ function run.initialize(arg)
 
 
   -- keep a few blank lines around: https://merveilles.town/@akkartik/110084833821965708
-  love.window.setTitle('text.love - '..Editor_state.filename)
+  love.window.setTitle('view.love - '..Editor_state.filename)
 
 
 
@@ -100,7 +100,7 @@ function run.initialize_window_geometry()
   App.screen.resize(App.screen.width, App.screen.height, App.screen.flags)
 end
 
-function run.resize(w, h)
+function run.resize(w,h)
 --?   print(("Window resized to width: %d and height: %d."):format(w, h))
   App.screen.width, App.screen.height = w, h
   Text.redraw_all(Editor_state)
@@ -128,7 +128,7 @@ function run.file_drop(file)
 
 
   -- keep a few blank lines around: https://merveilles.town/@akkartik/110084833821965708
-  love.window.setTitle('text.love - '..Editor_state.filename)
+  love.window.setTitle('view.love - '..Editor_state.filename)
 
 
 
@@ -166,15 +166,15 @@ function absolutize(path)
   return path
 end
 
-function run.mouse_press(x,y, mouse_button)
+function run.mouse_press(x,y, mouse_button, is_touch, presses)
   Cursor_time = 0  -- ensure cursor is visible immediately after it moves
   love.keyboard.setTextInput(true)  -- bring up keyboard on touch screen
-  return edit.mouse_press(Editor_state, x,y, mouse_button)
+  return edit.mouse_press(Editor_state, x,y, mouse_button, is_touch, presses)
 end
 
-function run.mouse_release(x,y, mouse_button)
+function run.mouse_release(x,y, mouse_button, is_touch, presses)
   Cursor_time = 0  -- ensure cursor is visible immediately after it moves
-  return edit.mouse_release(Editor_state, x,y, mouse_button)
+  return edit.mouse_release(Editor_state, x,y, mouse_button, is_touch, presses)
 end
 
 function run.mouse_wheel_move(dx,dy)
@@ -187,9 +187,9 @@ function run.text_input(t)
   return edit.text_input(Editor_state, t)
 end
 
-function run.keychord_press(chord, key)
+function run.keychord_press(chord, key, scancode, is_repeat)
   Cursor_time = 0  -- ensure cursor is visible immediately after it moves
-  return edit.keychord_press(Editor_state, chord, key)
+  return edit.keychord_press(Editor_state, chord, key, scancode, is_repeat)
 end
 
 function run.key_release(key, scancode)
diff --git a/run_tests.lua b/run_tests.lua
index c5c4eff..bea2807 100644
--- a/run_tests.lua
+++ b/run_tests.lua
@@ -43,32 +43,3 @@ function test_drop_file()
   check_eq(Editor_state.lines[3].data, 'ghi', 'lines:3')
   edit.draw(Editor_state)
 end
-
-function test_drop_file_saves_previous()
-  App.screen.init{width=Editor_state.left+300, height=300}
-  -- initially editing a file called foo that hasn't been saved to filesystem yet
-  Editor_state.lines = load_array{'abc', 'def'}
-  Editor_state.filename = 'foo'
-  schedule_save(Editor_state)
-  -- now drag a new file bar from the filesystem
-  App.filesystem['bar'] = 'abc\ndef\nghi\n'
-  local fake_dropped_file = {
-    opened = false,
-    getFilename = function(self)
-                    return 'bar'
-                  end,
-    open = function(self)
-             self.opened = true
-           end,
-    lines = function(self)
-              assert(self.opened)
-              return App.filesystem['bar']:gmatch('[^\n]+')
-            end,
-    close = function(self)
-              self.opened = false
-            end,
-  }
-  App.filedropped(fake_dropped_file)
-  -- filesystem now contains a file called foo
-  check_eq(App.filesystem['foo'], 'abc\ndef\n', 'check')
-end
diff --git a/select.lua b/select.lua
index 78affdc..018ddef 100644
--- a/select.lua
+++ b/select.lua
@@ -79,60 +79,6 @@ function Text.mouse_pos(State)
   return screen_bottom1.line, Text.pos_at_end_of_screen_line(State, screen_bottom1)
 end
 
-function Text.cut_selection_and_record_undo_event(State)
-  if State.selection1.line == nil then return end
-  local result = Text.selection(State)
-  Text.delete_selection_and_record_undo_event(State)
-  return result
-end
-
-function Text.delete_selection_and_record_undo_event(State)
-  if State.selection1.line == nil then return end
-  local minl,maxl = minmax(State.selection1.line, State.cursor1.line)
-  local before = snapshot(State, minl, maxl)
-  Text.delete_selection_without_undo(State)
-  record_undo_event(State, {before=before, after=snapshot(State, State.cursor1.line)})
-end
-
-function Text.delete_selection_without_undo(State)
-  if State.selection1.line == nil then return end
-  -- min,max = sorted(State.selection1,State.cursor1)
-  local minl,minp = State.selection1.line,State.selection1.pos
-  local maxl,maxp = State.cursor1.line,State.cursor1.pos
-  if minl > maxl then
-    minl,maxl = maxl,minl
-    minp,maxp = maxp,minp
-  elseif minl == maxl then
-    if minp > maxp then
-      minp,maxp = maxp,minp
-    end
-  end
-  -- update State.cursor1 and State.selection1
-  State.cursor1.line = minl
-  State.cursor1.pos = minp
-  if Text.lt1(State.cursor1, State.screen_top1) then
-    State.screen_top1.line = State.cursor1.line
-    State.screen_top1.pos = Text.pos_at_start_of_screen_line(State, State.cursor1)
-  end
-  State.selection1 = {}
-  -- delete everything between min (inclusive) and max (exclusive)
-  Text.clear_screen_line_cache(State, minl)
-  local min_offset = Text.offset(State.lines[minl].data, minp)
-  local max_offset = Text.offset(State.lines[maxl].data, maxp)
-  if minl == maxl then
---?     print('minl == maxl')
-    State.lines[minl].data = State.lines[minl].data:sub(1, min_offset-1)..State.lines[minl].data:sub(max_offset)
-    return
-  end
-  assert(minl < maxl, ('minl %d not < maxl %d'):format(minl, maxl))
-  local rhs = State.lines[maxl].data:sub(max_offset)
-  for i=maxl,minl+1,-1 do
-    table.remove(State.lines, i)
-    table.remove(State.line_cache, i)
-  end
-  State.lines[minl].data = State.lines[minl].data:sub(1, min_offset-1)..rhs
-end
-
 function Text.selection(State)
   if State.selection1.line == nil then return end
   -- min,max = sorted(State.selection1,State.cursor1)
diff --git a/source.lua b/source.lua
index 0644195..a998b67 100644
--- a/source.lua
+++ b/source.lua
@@ -56,7 +56,7 @@ function source.initialize_globals()
 end
 
 -- called only for real run
-function source.initialize()
+function source.initialize(arg, unfiltered_arg)
   log_new('source')
   if Settings and Settings.source then
     source.load_settings()
@@ -74,7 +74,7 @@ function source.initialize()
 
 
   -- keep a few blank lines around: https://merveilles.town/@akkartik/110084833821965708
-  love.window.setTitle('text.love - source - '..Editor_state.filename)
+  love.window.setTitle('view.love - source - '..Editor_state.filename)
 
 
 
@@ -173,7 +173,7 @@ function source.initialize_window_geometry()
   App.screen.resize(App.screen.width, App.screen.height, App.screen.flags)
 end
 
-function source.resize(w, h)
+function source.resize(w,h)
 --?   print(("Window resized to width: %d and height: %d."):format(w, h))
   App.screen.width, App.screen.height = w, h
   Text.redraw_all(Editor_state)
@@ -207,7 +207,7 @@ function source.file_drop(file)
 
 
   -- keep a few blank lines around: https://merveilles.town/@akkartik/110084833821965708
-  love.window.setTitle('text.love - source')
+  love.window.setTitle('view.love - source')
 
 
 
@@ -283,7 +283,7 @@ function source.settings()
   }
 end
 
-function source.mouse_press(x,y, mouse_button)
+function source.mouse_press(x,y, mouse_button, is_touch, presses)
   Cursor_time = 0  -- ensure cursor is visible immediately after it moves
   love.keyboard.setTextInput(true)  -- bring up keyboard on touch screen
 --?   print('mouse click', x, y)
@@ -291,7 +291,7 @@ function source.mouse_press(x,y, mouse_button)
 --?   print(Log_browser_state.left, Log_browser_state.right)
   if Show_file_navigator and y < Menu_status_bar_height + File_navigation.num_lines * Editor_state.line_height then
     -- send click to buttons
-    edit.mouse_press(Editor_state, x,y, mouse_button)
+    edit.mouse_press(Editor_state, x,y, mouse_button, is_touch, presses)
     return
   end
   if x < Editor_state.right + Margin_right then
@@ -300,23 +300,23 @@ function source.mouse_press(x,y, mouse_button)
       Focus = 'edit'
       return
     end
-    edit.mouse_press(Editor_state, x,y, mouse_button)
+    edit.mouse_press(Editor_state, x,y, mouse_button, is_touch, presses)
   elseif Show_log_browser_side and Log_browser_state.left <= x and x < Log_browser_state.right then
 --?     print('click on log_browser side')
     if Focus ~= 'log_browser' then
       Focus = 'log_browser'
       return
     end
-    log_browser.mouse_press(Log_browser_state, x,y, mouse_button)
+    log_browser.mouse_press(Log_browser_state, x,y, mouse_button, is_touch, presses)
   end
 end
 
-function source.mouse_release(x,y, mouse_button)
+function source.mouse_release(x,y, mouse_button, is_touch, presses)
   Cursor_time = 0  -- ensure cursor is visible immediately after it moves
   if Focus == 'edit' then
-    return edit.mouse_release(Editor_state, x,y, mouse_button)
+    return edit.mouse_release(Editor_state, x,y, mouse_button, is_touch, presses)
   else
-    return log_browser.mouse_release(Log_browser_state, x,y, mouse_button)
+    return log_browser.mouse_release(Log_browser_state, x,y, mouse_button, is_touch, presses)
   end
 end
 
@@ -342,7 +342,7 @@ function source.text_input(t)
   end
 end
 
-function source.keychord_press(chord, key)
+function source.keychord_press(chord, key, scancode, is_repeat)
   Cursor_time = 0  -- ensure cursor is visible immediately after it moves
 --?   print('source keychord')
   if Show_file_navigator then
@@ -382,9 +382,9 @@ function source.keychord_press(chord, key)
     return
   end
   if Focus == 'edit' then
-    return edit.keychord_press(Editor_state, chord, key)
+    return edit.keychord_press(Editor_state, chord, key, scancode, is_repeat)
   else
-    return log_browser.keychord_press(Log_browser_state, chord, key)
+    return log_browser.keychord_press(Log_browser_state, chord, key, scancode, is_repeat)
   end
 end
 
@@ -393,6 +393,6 @@ function source.key_release(key, scancode)
   if Focus == 'edit' then
     return edit.key_release(Editor_state, key, scancode)
   else
-    return log_browser.keychord_press(Log_browser_state, chordkey, scancode)
+    return log_browser.key_release(Log_browser_state, key, scancode)
   end
 end
diff --git a/source_edit.lua b/source_edit.lua
index a8dd682..77487ea 100644
--- a/source_edit.lua
+++ b/source_edit.lua
@@ -143,13 +143,13 @@ end
 
 function edit.put_cursor_on_next_text_line(State)
   local line = State.cursor1.line
-  while line < #State.lines do
+  if State.lines[line].mode == 'text' then return end
+  while line <= #State.lines and State.lines[line].mode ~= 'text' do
     line = line+1
-    if State.lines[line].mode == 'text' then
-      State.cursor1.line = line
-      State.cursor1.pos = 1
-      break
-    end
+  end
+  if line <= #State.lines and State.lines[line].mode == 'text' then
+    State.cursor1.line = line
+    State.cursor1.pos = 1
   end
 end
 
@@ -232,7 +232,7 @@ function edit.quit(State)
   end
 end
 
-function edit.mouse_press(State, x,y, mouse_button)
+function edit.mouse_press(State, x,y, mouse_button, is_touch, presses)
   if State.search_term then return end
   State.mouse_down = mouse_button
 --?   print_and_log(('edit.mouse_press: cursor at %d,%d'):format(State.cursor1.line, State.cursor1.pos))
@@ -279,7 +279,7 @@ function edit.mouse_press(State, x,y, mouse_button)
         State.lines.current_drawing_index = line_index
         State.lines.current_drawing = line
         Drawing.before = snapshot(State, line_index)
-        Drawing.mouse_press(State, line_index, x,y, mouse_button)
+        Drawing.mouse_press(State, line_index, x,y, mouse_button, is_touch, presses)
         return
       end
     end
@@ -292,12 +292,12 @@ function edit.mouse_press(State, x,y, mouse_button)
   State.selection1 = Text.final_text_loc_on_screen(State)
 end
 
-function edit.mouse_release(State, x,y, mouse_button)
+function edit.mouse_release(State, x,y, mouse_button, is_touch, presses)
   if State.search_term then return end
 --?   print_and_log(('edit.mouse_release: cursor at %d,%d'):format(State.cursor1.line, State.cursor1.pos))
   State.mouse_down = nil
   if State.lines.current_drawing then
-    Drawing.mouse_release(State, x,y, mouse_button)
+    Drawing.mouse_release(State, x,y, mouse_button, is_touch, presses)
     if Drawing.before then
       record_undo_event(State, {before=Drawing.before, after=snapshot(State, State.lines.current_drawing_index)})
       Drawing.before = nil
@@ -383,7 +383,7 @@ function edit.text_input(State, t)
   schedule_save(State)
 end
 
-function edit.keychord_press(State, chord, key)
+function edit.keychord_press(State, chord, key, scancode, is_repeat)
   if State.selection1.line and
       not State.lines.current_drawing and
       -- printable character created using shift key => delete selection
@@ -502,7 +502,7 @@ function edit.keychord_press(State, chord, key)
     local drawing_index, drawing = Drawing.current_drawing(State)
     if drawing_index then
       local before = snapshot(State, drawing_index)
-      Drawing.keychord_press(State, chord)
+      Drawing.keychord_press(State, chord, key, scancode, is_repeat)
       record_undo_event(State, {before=before, after=snapshot(State, drawing_index)})
       schedule_save(State)
     end
@@ -535,7 +535,7 @@ function edit.keychord_press(State, chord, key)
     end
     schedule_save(State)
   else
-    Text.keychord_press(State, chord)
+    Text.keychord_press(State, chord, key, scancode, is_repeat)
   end
 end
 
diff --git a/source_text.lua b/source_text.lua
index 284ed00..c281acf 100644
--- a/source_text.lua
+++ b/source_text.lua
@@ -223,7 +223,7 @@ function Text.insert_at_cursor(State, t)
 end
 
 -- Don't handle any keys here that would trigger text_input above.
-function Text.keychord_press(State, chord)
+function Text.keychord_press(State, chord, key, scancode, is_repeat)
 --?   print('chord', chord, State.selection1.line, State.selection1.pos)
   --== shortcuts that mutate text
   if chord == 'return' then
diff --git a/source_undo.lua b/source_undo.lua
index d91fecd..772e5da 100644
--- a/source_undo.lua
+++ b/source_undo.lua
@@ -84,12 +84,12 @@ end
 -- https://stackoverflow.com/questions/640642/how-do-you-copy-a-lua-table-by-value/26367080#26367080
 function deepcopy(obj, seen)
   if type(obj) ~= 'table' then return obj end
-  if seen and seen[obj] then return seen[obj] end
-  local s = seen or {}
+  seen = seen or {}
+  if seen[obj] then return seen[obj] end
   local result = setmetatable({}, getmetatable(obj))
-  s[obj] = result
+  seen[obj] = result
   for k,v in pairs(obj) do
-    result[deepcopy(k, s)] = deepcopy(v, s)
+    result[deepcopy(k, seen)] = deepcopy(v, seen)
   end
   return result
 end
diff --git a/text.lua b/text.lua
index da4d2a1..a417fab 100644
--- a/text.lua
+++ b/text.lua
@@ -38,12 +38,10 @@ function Text.draw(State, line_index, y, startpos)
           end
         else
           if pos <= State.cursor1.pos and pos + frag_len > State.cursor1.pos then
-            Text.draw_cursor(State, State.left+Text.x(State.font, screen_line, State.cursor1.pos-pos+1), y)
+            Text.pretend_draw_cursor(State, State.left+Text.x(State.font, screen_line, State.cursor1.pos-pos+1), y)
           elseif pos + frag_len == State.cursor1.pos then
-            -- Show cursor at end of line.
-            -- This place also catches end of wrapping screen lines. That doesn't seem worth distinguishing.
-            -- It seems useful to see a cursor whether your eye is on the left or right margin.
-            Text.draw_cursor(State, State.left+Text.x(State.font, screen_line, State.cursor1.pos-pos+1), y)
+            -- Keep pretend cursor_x/cursor_y in sync with upstream.
+            Text.pretend_draw_cursor(State, State.left+Text.x(State.font, screen_line, State.cursor1.pos-pos+1), y)
           end
         end
       end
@@ -80,6 +78,11 @@ function Text.draw_cursor(State, x, y)
   State.cursor_y = y+State.line_height
 end
 
+function Text.pretend_draw_cursor(State, x, y)
+  State.cursor_x = x
+  State.cursor_y = y+State.line_height
+end
+
 function Text.populate_screen_line_starting_pos(State, line_index)
   local line = State.lines[line_index]
   local line_cache = State.line_cache[line_index]
@@ -129,124 +132,13 @@ function Text.text_input(State, t)
       -- Key mutated by the keyboard layout. Continue below.
     end
   end
-  local before = snapshot(State, State.cursor1.line)
---?   print(State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos)
-  Text.insert_at_cursor(State, t)
-  if State.cursor_y > App.screen.height - State.line_height then
-    Text.populate_screen_line_starting_pos(State, State.cursor1.line)
-    Text.snap_cursor_to_bottom_of_screen(State, State.left, State.right)
-  end
-  record_undo_event(State, {before=before, after=snapshot(State, State.cursor1.line)})
-end
-
-function Text.insert_at_cursor(State, t)
-  local byte_offset = Text.offset(State.lines[State.cursor1.line].data, State.cursor1.pos)
-  State.lines[State.cursor1.line].data = string.sub(State.lines[State.cursor1.line].data, 1, byte_offset-1)..t..string.sub(State.lines[State.cursor1.line].data, byte_offset)
-  Text.clear_screen_line_cache(State, State.cursor1.line)
-  State.cursor1.pos = State.cursor1.pos+1
 end
 
 -- Don't handle any keys here that would trigger text_input above.
-function Text.keychord_press(State, chord)
+function Text.keychord_press(State, chord, key, scancode, is_repeat)
 --?   print('chord', chord, State.selection1.line, State.selection1.pos)
-  --== shortcuts that mutate text (must schedule_save)
-  if chord == 'return' then
-    local before_line = State.cursor1.line
-    local before = snapshot(State, before_line)
-    Text.insert_return(State)
-    if State.cursor_y > App.screen.height - State.line_height then
-      Text.snap_cursor_to_bottom_of_screen(State, State.left, State.right)
-    end
-    record_undo_event(State, {before=before, after=snapshot(State, before_line, State.cursor1.line)})
-    schedule_save(State)
-  elseif chord == 'tab' then
-    local before = snapshot(State, State.cursor1.line)
---?     print(State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos)
-    Text.insert_at_cursor(State, '\t')
-    if State.cursor_y > App.screen.height - State.line_height then
-      Text.populate_screen_line_starting_pos(State, State.cursor1.line)
-      Text.snap_cursor_to_bottom_of_screen(State, State.left, State.right)
---?       print('=>', State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos)
-    end
-    record_undo_event(State, {before=before, after=snapshot(State, State.cursor1.line)})
-    schedule_save(State)
-  elseif chord == 'backspace' then
-    if State.selection1.line then
-      Text.delete_selection_and_record_undo_event(State)
-      schedule_save(State)
-      return
-    end
-    local before
-    if State.cursor1.pos > 1 then
-      before = snapshot(State, State.cursor1.line)
-      local byte_start = utf8.offset(State.lines[State.cursor1.line].data, State.cursor1.pos-1)
-      local byte_end = utf8.offset(State.lines[State.cursor1.line].data, State.cursor1.pos)
-      if byte_start then
-        if byte_end then
-          State.lines[State.cursor1.line].data = string.sub(State.lines[State.cursor1.line].data, 1, byte_start-1)..string.sub(State.lines[State.cursor1.line].data, byte_end)
-        else
-          State.lines[State.cursor1.line].data = string.sub(State.lines[State.cursor1.line].data, 1, byte_start-1)
-        end
-        State.cursor1.pos = State.cursor1.pos-1
-      end
-    elseif State.cursor1.line > 1 then
-      before = snapshot(State, State.cursor1.line-1, State.cursor1.line)
-      -- join lines
-      State.cursor1.pos = utf8.len(State.lines[State.cursor1.line-1].data)+1
-      State.lines[State.cursor1.line-1].data = State.lines[State.cursor1.line-1].data..State.lines[State.cursor1.line].data
-      table.remove(State.lines, State.cursor1.line)
-      table.remove(State.line_cache, State.cursor1.line)
-      State.cursor1.line = State.cursor1.line-1
-    end
-    if State.screen_top1.line > #State.lines then
-      Text.populate_screen_line_starting_pos(State, #State.lines)
-      local line_cache = State.line_cache[#State.line_cache]
-      State.screen_top1 = {line=#State.lines, pos=line_cache.screen_line_starting_pos[#line_cache.screen_line_starting_pos]}
-    elseif Text.lt1(State.cursor1, State.screen_top1) then
-      State.screen_top1 = {
-        line=State.cursor1.line,
-        pos=Text.pos_at_start_of_screen_line(State, State.cursor1),
-      }
-      Text.redraw_all(State)  -- if we're scrolling, reclaim all line caches to avoid memory leaks
-    end
-    Text.clear_screen_line_cache(State, State.cursor1.line)
-    assert(Text.le1(State.screen_top1, State.cursor1), ('screen_top (line=%d,pos=%d) is below cursor (line=%d,pos=%d)'):format(State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos))
-    record_undo_event(State, {before=before, after=snapshot(State, State.cursor1.line)})
-    schedule_save(State)
-  elseif chord == 'delete' then
-    if State.selection1.line then
-      Text.delete_selection_and_record_undo_event(State)
-      schedule_save(State)
-      return
-    end
-    local before
-    if State.cursor1.pos <= utf8.len(State.lines[State.cursor1.line].data) then
-      before = snapshot(State, State.cursor1.line)
-    else
-      before = snapshot(State, State.cursor1.line, State.cursor1.line+1)
-    end
-    if State.cursor1.pos <= utf8.len(State.lines[State.cursor1.line].data) then
-      local byte_start = utf8.offset(State.lines[State.cursor1.line].data, State.cursor1.pos)
-      local byte_end = utf8.offset(State.lines[State.cursor1.line].data, State.cursor1.pos+1)
-      if byte_start then
-        if byte_end then
-          State.lines[State.cursor1.line].data = string.sub(State.lines[State.cursor1.line].data, 1, byte_start-1)..string.sub(State.lines[State.cursor1.line].data, byte_end)
-        else
-          State.lines[State.cursor1.line].data = string.sub(State.lines[State.cursor1.line].data, 1, byte_start-1)
-        end
-        -- no change to State.cursor1.pos
-      end
-    elseif State.cursor1.line < #State.lines then
-      -- join lines
-      State.lines[State.cursor1.line].data = State.lines[State.cursor1.line].data..State.lines[State.cursor1.line+1].data
-      table.remove(State.lines, State.cursor1.line+1)
-      table.remove(State.line_cache, State.cursor1.line+1)
-    end
-    Text.clear_screen_line_cache(State, State.cursor1.line)
-    record_undo_event(State, {before=before, after=snapshot(State, State.cursor1.line)})
-    schedule_save(State)
   --== shortcuts that move the cursor
-  elseif chord == 'left' then
+  if chord == 'left' then
     Text.left(State)
     State.selection1 = {}
   elseif chord == 'right' then
@@ -330,15 +222,6 @@ function Text.keychord_press(State, chord)
   end
 end
 
-function Text.insert_return(State)
-  local byte_offset = Text.offset(State.lines[State.cursor1.line].data, State.cursor1.pos)
-  table.insert(State.lines, State.cursor1.line+1, {data=string.sub(State.lines[State.cursor1.line].data, byte_offset)})
-  table.insert(State.line_cache, State.cursor1.line+1, {})
-  State.lines[State.cursor1.line].data = string.sub(State.lines[State.cursor1.line].data, 1, byte_offset-1)
-  Text.clear_screen_line_cache(State, State.cursor1.line)
-  State.cursor1 = {line=State.cursor1.line+1, pos=1}
-end
-
 function Text.pageup(State)
   State.screen_top1 = Text.previous_screen_top1(State)
   State.cursor1 = deepcopy(State.screen_top1)
diff --git a/text_tests.lua b/text_tests.lua
index 962de7d..79c38c5 100644
--- a/text_tests.lua
+++ b/text_tests.lua
@@ -15,43 +15,6 @@ function test_initial_state()
   check_eq(Editor_state.screen_top1.pos, 1, 'screen_top:pos')
 end
 
-function test_backspace_from_start_of_final_line()
-  -- display final line of text with cursor at start of it
-  App.screen.init{width=120, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'def'}
-  Editor_state.screen_top1 = {line=2, pos=1}
-  Editor_state.cursor1 = {line=2, pos=1}
-  Text.redraw_all(Editor_state)
-  -- backspace scrolls up
-  edit.run_after_keychord(Editor_state, 'backspace', 'backspace')
-  check_eq(#Editor_state.lines, 1, '#lines')
-  check_eq(Editor_state.cursor1.line, 1, 'cursor')
-  check_eq(Editor_state.screen_top1.line, 1, 'screen_top')
-end
-
-function test_insert_first_character()
-  App.screen.init{width=120, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{}
-  Text.redraw_all(Editor_state)
-  edit.draw(Editor_state)
-  edit.run_after_text_input(Editor_state, 'a')
-  local y = Editor_state.top
-  App.screen.check(y, 'a', 'screen:1')
-end
-
-function test_press_ctrl()
-  -- press ctrl while the cursor is on text
-  App.screen.init{width=50, height=80}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{''}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=1, pos=1}
-  Editor_state.screen_top1 = {line=1, pos=1}
-  edit.run_after_keychord(Editor_state, 'C-m', 'm')
-end
-
 function test_move_left()
   App.screen.init{width=120, height=60}
   Editor_state = edit.initialize_test_state()
@@ -575,43 +538,6 @@ function test_cursor_movement_without_shift_resets_selection()
   check_eq(Editor_state.lines[1].data, 'abc', 'data')
 end
 
-function test_edit_deletes_selection()
-  -- display a line of text with some part selected
-  App.screen.init{width=75, height=80}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=1, pos=1}
-  Editor_state.selection1 = {line=1, pos=2}
-  Editor_state.screen_top1 = {line=1, pos=1}
-  edit.draw(Editor_state)
-  -- press a key
-  edit.run_after_text_input(Editor_state, 'x')
-  -- selected text is deleted and replaced with the key
-  check_eq(Editor_state.lines[1].data, 'xbc', 'check')
-end
-
-function test_edit_with_shift_key_deletes_selection()
-  -- display a line of text with some part selected
-  App.screen.init{width=75, height=80}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=1, pos=1}
-  Editor_state.selection1 = {line=1, pos=2}
-  Editor_state.screen_top1 = {line=1, pos=1}
-  edit.draw(Editor_state)
-  -- mimic precise keypresses for a capital letter
-  App.fake_key_press('lshift')
-  edit.keychord_press(Editor_state, 'd', 'd')
-  edit.text_input(Editor_state, 'D')
-  edit.key_release(Editor_state, 'd')
-  App.fake_key_release('lshift')
-  -- selected text is deleted and replaced with the key
-  check_nil(Editor_state.selection1.line, 'check')
-  check_eq(Editor_state.lines[1].data, 'Dbc', 'data')
-end
-
 function test_copy_does_not_reset_selection()
   -- display a line of text with a selection
   App.screen.init{width=75, height=80}
@@ -629,154 +555,21 @@ function test_copy_does_not_reset_selection()
   check(Editor_state.selection1.line, 'check')
 end
 
-function test_cut()
-  -- display a line of text with some part selected
-  App.screen.init{width=75, height=80}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=1, pos=1}
-  Editor_state.selection1 = {line=1, pos=2}
-  Editor_state.screen_top1 = {line=1, pos=1}
-  edit.draw(Editor_state)
-  -- press a key
-  edit.run_after_keychord(Editor_state, 'C-x', 'x')
-  check_eq(App.clipboard, 'a', 'clipboard')
-  -- selected text is deleted
-  check_eq(Editor_state.lines[1].data, 'bc', 'data')
-end
-
-function test_paste_replaces_selection()
-  -- display a line of text with a selection
-  App.screen.init{width=75, height=80}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'def'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=2, pos=1}
-  Editor_state.selection1 = {line=1, pos=1}
-  Editor_state.screen_top1 = {line=1, pos=1}
-  edit.draw(Editor_state)
-  -- set clipboard
-  App.clipboard = 'xyz'
-  -- paste selection
-  edit.run_after_keychord(Editor_state, 'C-v', 'v')
-  -- selection is reset since shift key is not pressed
-  -- selection includes the newline, so it's also deleted
-  check_eq(Editor_state.lines[1].data, 'xyzdef', 'check')
-end
-
-function test_deleting_selection_may_scroll()
-  -- display lines 2/3/4
-  App.screen.init{width=120, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=3, pos=2}
-  Editor_state.screen_top1 = {line=2, pos=1}
-  edit.draw(Editor_state)
-  local y = Editor_state.top
-  App.screen.check(y, 'def', 'baseline/screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'ghi', 'baseline/screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'jkl', 'baseline/screen:3')
-  -- set up a selection starting above the currently displayed page
-  Editor_state.selection1 = {line=1, pos=2}
-  -- delete selection
-  edit.run_after_keychord(Editor_state, 'backspace', 'backspace')
-  -- page scrolls up
-  check_eq(Editor_state.screen_top1.line, 1, 'check')
-  check_eq(Editor_state.lines[1].data, 'ahi', 'data')
-end
+function test_move_cursor_using_mouse()
 
-function test_edit_wrapping_text()
   App.screen.init{width=50, height=60}
   Editor_state = edit.initialize_test_state()
   Editor_state.lines = load_array{'abc', 'def', 'xyz'}
   Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=2, pos=4}
-  Editor_state.screen_top1 = {line=1, pos=1}
-  edit.draw(Editor_state)
-  edit.run_after_text_input(Editor_state, 'g')
-  local y = Editor_state.top
-  App.screen.check(y, 'abc', 'screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'de', 'screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'fg', 'screen:3')
-end
-
-function test_insert_newline()
-  -- display a few lines
-  App.screen.init{width=Editor_state.left+30, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=1, pos=2}
-  Editor_state.screen_top1 = {line=1, pos=1}
-  edit.draw(Editor_state)
-  local y = Editor_state.top
-  App.screen.check(y, 'abc', 'baseline/screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'def', 'baseline/screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'ghi', 'baseline/screen:3')
-  -- hitting the enter key splits the line
-  edit.run_after_keychord(Editor_state, 'return', 'return')
-  check_eq(Editor_state.screen_top1.line, 1, 'screen_top')
-  check_eq(Editor_state.cursor1.line, 2, 'cursor:line')
-  check_eq(Editor_state.cursor1.pos, 1, 'cursor:pos')
-  y = Editor_state.top
-  App.screen.check(y, 'a', 'screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'bc', 'screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'def', 'screen:3')
-end
-
-function test_insert_newline_at_start_of_line()
-  -- display a line
-  App.screen.init{width=Editor_state.left+30, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc'}
-  Text.redraw_all(Editor_state)
   Editor_state.cursor1 = {line=1, pos=1}
   Editor_state.screen_top1 = {line=1, pos=1}
-  -- hitting the enter key splits the line
-  edit.run_after_keychord(Editor_state, 'return', 'return')
-  check_eq(Editor_state.cursor1.line, 2, 'cursor:line')
-  check_eq(Editor_state.cursor1.pos, 1, 'cursor:pos')
-  check_eq(Editor_state.lines[1].data, '', 'data:1')
-  check_eq(Editor_state.lines[2].data, 'abc', 'data:2')
-end
-
-function test_insert_from_clipboard()
-  -- display a few lines
-  App.screen.init{width=Editor_state.left+30, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=1, pos=2}
-  Editor_state.screen_top1 = {line=1, pos=1}
-  edit.draw(Editor_state)
-  local y = Editor_state.top
-  App.screen.check(y, 'abc', 'baseline/screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'def', 'baseline/screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'ghi', 'baseline/screen:3')
-  -- paste some text including a newline, check that new line is created
-  App.clipboard = 'xy\nz'
-  edit.run_after_keychord(Editor_state, 'C-v', 'v')
-  check_eq(Editor_state.screen_top1.line, 1, 'screen_top')
-  check_eq(Editor_state.cursor1.line, 2, 'cursor:line')
+  Editor_state.selection1 = {}
+  edit.draw(Editor_state)  -- populate line_cache.startpos for each line
+  edit.run_after_mouse_release(Editor_state, Editor_state.left+8,Editor_state.top+5, 1)
+  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
   check_eq(Editor_state.cursor1.pos, 2, 'cursor:pos')
-  y = Editor_state.top
-  App.screen.check(y, 'axy', 'screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'zbc', 'screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'def', 'screen:3')
+  check_nil(Editor_state.selection1.line, 'selection:line')
+  check_nil(Editor_state.selection1.pos, 'selection:pos')
 end
 
 function test_select_text_using_mouse()
@@ -930,22 +723,6 @@ function test_select_all_text()
   check_eq(Editor_state.cursor1.pos, 8, 'cursor:pos')
 end
 
-function test_cut_without_selection()
-  -- display a few lines
-  App.screen.init{width=Editor_state.left+30, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=1, pos=2}
-  Editor_state.screen_top1 = {line=1, pos=1}
-  Editor_state.selection1 = {}
-  edit.draw(Editor_state)
-  -- try to cut without selecting text
-  edit.run_after_keychord(Editor_state, 'C-x', 'x')
-  -- no crash
-  check_nil(Editor_state.selection1.line, 'check')
-end
-
 function test_pagedown()
   App.screen.init{width=120, height=45}
   Editor_state = edit.initialize_test_state()
@@ -1376,104 +1153,6 @@ function test_pageup_scrolls_up_from_middle_screen_line()
   App.screen.check(y, 'ghi ', 'screen:3')
 end
 
-function test_enter_on_bottom_line_scrolls_down()
-  -- display a few lines with cursor on bottom line
-  App.screen.init{width=Editor_state.left+30, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=3, pos=2}
-  Editor_state.screen_top1 = {line=1, pos=1}
-  edit.draw(Editor_state)
-  local y = Editor_state.top
-  App.screen.check(y, 'abc', 'baseline/screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'def', 'baseline/screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'ghi', 'baseline/screen:3')
-  -- after hitting the enter key the screen scrolls down
-  edit.run_after_keychord(Editor_state, 'return', 'return')
-  check_eq(Editor_state.screen_top1.line, 2, 'screen_top')
-  check_eq(Editor_state.cursor1.line, 4, 'cursor:line')
-  check_eq(Editor_state.cursor1.pos, 1, 'cursor:pos')
-  y = Editor_state.top
-  App.screen.check(y, 'def', 'screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'g', 'screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'hi', 'screen:3')
-end
-
-function test_enter_on_final_line_avoids_scrolling_down_when_not_at_bottom()
-  -- display just the bottom line on screen
-  App.screen.init{width=Editor_state.left+30, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=4, pos=2}
-  Editor_state.screen_top1 = {line=4, pos=1}
-  edit.draw(Editor_state)
-  local y = Editor_state.top
-  App.screen.check(y, 'jkl', 'baseline/screen:1')
-  -- after hitting the enter key the screen does not scroll down
-  edit.run_after_keychord(Editor_state, 'return', 'return')
-  check_eq(Editor_state.screen_top1.line, 4, 'screen_top')
-  check_eq(Editor_state.cursor1.line, 5, 'cursor:line')
-  check_eq(Editor_state.cursor1.pos, 1, 'cursor:pos')
-  y = Editor_state.top
-  App.screen.check(y, 'j', 'screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'kl', 'screen:2')
-end
-
-function test_inserting_text_on_final_line_avoids_scrolling_down_when_not_at_bottom()
-  -- display just an empty bottom line on screen
-  App.screen.init{width=Editor_state.left+30, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', ''}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=2, pos=1}
-  Editor_state.screen_top1 = {line=2, pos=1}
-  edit.draw(Editor_state)
-  -- after hitting the inserting_text key the screen does not scroll down
-  edit.run_after_text_input(Editor_state, 'a')
-  check_eq(Editor_state.screen_top1.line, 2, 'screen_top')
-  check_eq(Editor_state.cursor1.line, 2, 'cursor:line')
-  check_eq(Editor_state.cursor1.pos, 2, 'cursor:pos')
-  local y = Editor_state.top
-  App.screen.check(y, 'a', 'screen:1')
-end
-
-function test_typing_on_bottom_line_scrolls_down()
-  -- display a few lines with cursor on bottom line
-  App.screen.init{width=Editor_state.left+30, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=3, pos=4}
-  Editor_state.screen_top1 = {line=1, pos=1}
-  edit.draw(Editor_state)
-  local y = Editor_state.top
-  App.screen.check(y, 'abc', 'baseline/screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'def', 'baseline/screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'ghi', 'baseline/screen:3')
-  -- after typing something the line wraps and the screen scrolls down
-  edit.run_after_text_input(Editor_state, 'j')
-  edit.run_after_text_input(Editor_state, 'k')
-  edit.run_after_text_input(Editor_state, 'l')
-  check_eq(Editor_state.screen_top1.line, 2, 'screen_top')
-  check_eq(Editor_state.cursor1.line, 3, 'cursor:line')
-  check_eq(Editor_state.cursor1.pos, 7, 'cursor:pos')
-  y = Editor_state.top
-  App.screen.check(y, 'def', 'screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'ghij', 'screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'kl', 'screen:3')
-end
-
 function test_left_arrow_scrolls_up_in_wrapped_line()
   -- display lines starting from second screen line of a line
   App.screen.init{width=Editor_state.left+30, height=60}
@@ -1588,293 +1267,6 @@ function test_end_scrolls_down_in_wrapped_line()
   App.screen.check(y, 'jkl', 'screen:3')
 end
 
-function test_position_cursor_on_recently_edited_wrapping_line()
-  -- draw a line wrapping over 2 screen lines
-  App.screen.init{width=100, height=200}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc def ghi jkl mno pqr ', 'xyz'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=1, pos=25}
-  Editor_state.screen_top1 = {line=1, pos=1}
-  edit.draw(Editor_state)
-  local y = Editor_state.top
-  App.screen.check(y, 'abc def ghi ', 'baseline1/screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'jkl mno pqr ', 'baseline1/screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'xyz', 'baseline1/screen:3')
-  -- add to the line until it's wrapping over 3 screen lines
-  edit.run_after_text_input(Editor_state, 's')
-  edit.run_after_text_input(Editor_state, 't')
-  edit.run_after_text_input(Editor_state, 'u')
-  check_eq(Editor_state.cursor1.pos, 28, 'cursor:pos')
-  y = Editor_state.top
-  App.screen.check(y, 'abc def ghi ', 'baseline2/screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'jkl mno pqr ', 'baseline2/screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'stu', 'baseline2/screen:3')
-  -- try to move the cursor earlier in the third screen line by clicking the mouse
-  edit.run_after_mouse_release(Editor_state, Editor_state.left+2,Editor_state.top+Editor_state.line_height*2+5, 1)
-  -- cursor should move
-  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
-  check_eq(Editor_state.cursor1.pos, 25, 'cursor:pos')
-end
-
-function test_backspace_can_scroll_up()
-  -- display the lines 2/3/4 with the cursor on line 2
-  App.screen.init{width=120, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=2, pos=1}
-  Editor_state.screen_top1 = {line=2, pos=1}
-  edit.draw(Editor_state)
-  local y = Editor_state.top
-  App.screen.check(y, 'def', 'baseline/screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'ghi', 'baseline/screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'jkl', 'baseline/screen:3')
-  -- after hitting backspace the screen scrolls up by one line
-  edit.run_after_keychord(Editor_state, 'backspace', 'backspace')
-  check_eq(Editor_state.screen_top1.line, 1, 'screen_top')
-  check_eq(Editor_state.cursor1.line, 1, 'cursor')
-  y = Editor_state.top
-  App.screen.check(y, 'abcdef', 'screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'ghi', 'screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'jkl', 'screen:3')
-end
-
-function test_backspace_can_scroll_up_screen_line()
-  -- display lines starting from second screen line of a line
-  App.screen.init{width=Editor_state.left+30, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'def', 'ghi jkl', 'mno'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=3, pos=5}
-  Editor_state.screen_top1 = {line=3, pos=5}
-  edit.draw(Editor_state)
-  local y = Editor_state.top
-  App.screen.check(y, 'jkl', 'baseline/screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'mno', 'baseline/screen:2')
-  -- after hitting backspace the screen scrolls up by one screen line
-  edit.run_after_keychord(Editor_state, 'backspace', 'backspace')
-  y = Editor_state.top
-  App.screen.check(y, 'ghij', 'screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'kl', 'screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'mno', 'screen:3')
-  check_eq(Editor_state.screen_top1.line, 3, 'screen_top:line')
-  check_eq(Editor_state.screen_top1.pos, 1, 'screen_top:pos')
-  check_eq(Editor_state.cursor1.line, 3, 'cursor:line')
-  check_eq(Editor_state.cursor1.pos, 4, 'cursor:pos')
-end
-
-function test_backspace_past_line_boundary()
-  -- position cursor at start of a (non-first) line
-  App.screen.init{width=Editor_state.left+30, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'def'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=2, pos=1}
-  -- backspace joins with previous line
-  edit.run_after_keychord(Editor_state, 'backspace', 'backspace')
-  check_eq(Editor_state.lines[1].data, 'abcdef', 'check')
-end
-
--- some tests for operating over selections created using Shift- chords
--- we're just testing delete_selection, and it works the same for all keys
-
-function test_backspace_over_selection()
-  -- select just one character within a line with cursor before selection
-  App.screen.init{width=Editor_state.left+30, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl', 'mno'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=1, pos=1}
-  Editor_state.selection1 = {line=1, pos=2}
-  -- backspace deletes the selected character, even though it's after the cursor
-  edit.run_after_keychord(Editor_state, 'backspace', 'backspace')
-  check_eq(Editor_state.lines[1].data, 'bc', 'data')
-  -- cursor (remains) at start of selection
-  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
-  check_eq(Editor_state.cursor1.pos, 1, 'cursor:pos')
-  -- selection is cleared
-  check_nil(Editor_state.selection1.line, 'selection')
-end
-
-function test_backspace_over_selection_reverse()
-  -- select just one character within a line with cursor after selection
-  App.screen.init{width=Editor_state.left+30, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl', 'mno'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=1, pos=2}
-  Editor_state.selection1 = {line=1, pos=1}
-  -- backspace deletes the selected character
-  edit.run_after_keychord(Editor_state, 'backspace', 'backspace')
-  check_eq(Editor_state.lines[1].data, 'bc', 'data')
-  -- cursor moves to start of selection
-  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
-  check_eq(Editor_state.cursor1.pos, 1, 'cursor:pos')
-  -- selection is cleared
-  check_nil(Editor_state.selection1.line, 'selection')
-end
-
-function test_backspace_over_multiple_lines()
-  -- select just one character within a line with cursor after selection
-  App.screen.init{width=Editor_state.left+30, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl', 'mno'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=1, pos=2}
-  Editor_state.selection1 = {line=4, pos=2}
-  -- backspace deletes the region and joins the remaining portions of lines on either side
-  edit.run_after_keychord(Editor_state, 'backspace', 'backspace')
-  check_eq(Editor_state.lines[1].data, 'akl', 'data:1')
-  check_eq(Editor_state.lines[2].data, 'mno', 'data:2')
-  -- cursor remains at start of selection
-  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
-  check_eq(Editor_state.cursor1.pos, 2, 'cursor:pos')
-  -- selection is cleared
-  check_nil(Editor_state.selection1.line, 'selection')
-end
-
-function test_backspace_to_end_of_line()
-  -- select region from cursor to end of line
-  App.screen.init{width=Editor_state.left+30, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl', 'mno'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=1, pos=2}
-  Editor_state.selection1 = {line=1, pos=4}
-  -- backspace deletes rest of line without joining to any other line
-  edit.run_after_keychord(Editor_state, 'backspace', 'backspace')
-  check_eq(Editor_state.lines[1].data, 'a', 'data:1')
-  check_eq(Editor_state.lines[2].data, 'def', 'data:2')
-  -- cursor remains at start of selection
-  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
-  check_eq(Editor_state.cursor1.pos, 2, 'cursor:pos')
-  -- selection is cleared
-  check_nil(Editor_state.selection1.line, 'selection')
-end
-
-function test_backspace_to_start_of_line()
-  -- select region from cursor to start of line
-  App.screen.init{width=Editor_state.left+30, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl', 'mno'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=2, pos=1}
-  Editor_state.selection1 = {line=2, pos=3}
-  -- backspace deletes beginning of line without joining to any other line
-  edit.run_after_keychord(Editor_state, 'backspace', 'backspace')
-  check_eq(Editor_state.lines[1].data, 'abc', 'data:1')
-  check_eq(Editor_state.lines[2].data, 'f', 'data:2')
-  -- cursor remains at start of selection
-  check_eq(Editor_state.cursor1.line, 2, 'cursor:line')
-  check_eq(Editor_state.cursor1.pos, 1, 'cursor:pos')
-  -- selection is cleared
-  check_nil(Editor_state.selection1.line, 'selection')
-end
-
-function test_undo_insert_text()
-  App.screen.init{width=120, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'def', 'xyz'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=2, pos=4}
-  Editor_state.screen_top1 = {line=1, pos=1}
-  -- insert a character
-  edit.draw(Editor_state)
-  edit.run_after_text_input(Editor_state, 'g')
-  check_eq(Editor_state.cursor1.line, 2, 'baseline/cursor:line')
-  check_eq(Editor_state.cursor1.pos, 5, 'baseline/cursor:pos')
-  check_nil(Editor_state.selection1.line, 'baseline/selection:line')
-  check_nil(Editor_state.selection1.pos, 'baseline/selection:pos')
-  local y = Editor_state.top
-  App.screen.check(y, 'abc', 'baseline/screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'defg', 'baseline/screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'xyz', 'baseline/screen:3')
-  -- undo
-  edit.run_after_keychord(Editor_state, 'C-z', 'z')
-  check_eq(Editor_state.cursor1.line, 2, 'cursor:line')
-  check_eq(Editor_state.cursor1.pos, 4, 'cursor:pos')
-  check_nil(Editor_state.selection1.line, 'selection:line')
-  check_nil(Editor_state.selection1.pos, 'selection:pos')
-  y = Editor_state.top
-  App.screen.check(y, 'abc', 'screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'def', 'screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'xyz', 'screen:3')
-end
-
-function test_undo_delete_text()
-  App.screen.init{width=120, height=60}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc', 'defg', 'xyz'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=2, pos=5}
-  Editor_state.screen_top1 = {line=1, pos=1}
-  -- delete a character
-  edit.run_after_keychord(Editor_state, 'backspace', 'backspace')
-  check_eq(Editor_state.cursor1.line, 2, 'baseline/cursor:line')
-  check_eq(Editor_state.cursor1.pos, 4, 'baseline/cursor:pos')
-  check_nil(Editor_state.selection1.line, 'baseline/selection:line')
-  check_nil(Editor_state.selection1.pos, 'baseline/selection:pos')
-  local y = Editor_state.top
-  App.screen.check(y, 'abc', 'baseline/screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'def', 'baseline/screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'xyz', 'baseline/screen:3')
-  -- undo
---?   -- after undo, the backspaced key is selected
-  edit.run_after_keychord(Editor_state, 'C-z', 'z')
-  check_eq(Editor_state.cursor1.line, 2, 'cursor:line')
-  check_eq(Editor_state.cursor1.pos, 5, 'cursor:pos')
-  check_nil(Editor_state.selection1.line, 'selection:line')
-  check_nil(Editor_state.selection1.pos, 'selection:pos')
---?   check_eq(Editor_state.selection1.line, 2, 'selection:line')
---?   check_eq(Editor_state.selection1.pos, 4, 'selection:pos')
-  y = Editor_state.top
-  App.screen.check(y, 'abc', 'screen:1')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'defg', 'screen:2')
-  y = y + Editor_state.line_height
-  App.screen.check(y, 'xyz', 'screen:3')
-end
-
-function test_undo_restores_selection()
-  -- display a line of text with some part selected
-  App.screen.init{width=75, height=80}
-  Editor_state = edit.initialize_test_state()
-  Editor_state.lines = load_array{'abc'}
-  Text.redraw_all(Editor_state)
-  Editor_state.cursor1 = {line=1, pos=1}
-  Editor_state.selection1 = {line=1, pos=2}
-  Editor_state.screen_top1 = {line=1, pos=1}
-  edit.draw(Editor_state)
-  -- delete selected text
-  edit.run_after_text_input(Editor_state, 'x')
-  check_eq(Editor_state.lines[1].data, 'xbc', 'baseline')
-  check_nil(Editor_state.selection1.line, 'baseline:selection')
-  -- undo
-  edit.run_after_keychord(Editor_state, 'C-z', 'z')
-  edit.run_after_keychord(Editor_state, 'C-z', 'z')
-  -- selection is restored
-  check_eq(Editor_state.selection1.line, 1, 'line')
-  check_eq(Editor_state.selection1.pos, 2, 'pos')
-end
-
 function test_search()
   App.screen.init{width=120, height=60}
   Editor_state = edit.initialize_test_state()
diff --git a/undo.lua b/undo.lua
index e0cd730..4001fef 100644
--- a/undo.lua
+++ b/undo.lua
@@ -1,92 +1,12 @@
--- undo/redo by managing the sequence of events in the current session
--- based on https://github.com/akkartik/mu1/blob/master/edit/012-editor-undo.mu
-
--- makes a copy of lines on every single keystroke; will be inefficient with really long lines.
--- TODO: highlight stuff inserted by any undo/redo operation
--- TODO: coalesce multiple similar operations
-
-function record_undo_event(State, data)
-  State.history[State.next_history] = data
-  State.next_history = State.next_history+1
-  for i=State.next_history,#State.history do
-    State.history[i] = nil
-  end
-end
-
-function undo_event(State)
-  if State.next_history > 1 then
---?     print('moving to history', State.next_history-1)
-    State.next_history = State.next_history-1
-    local result = State.history[State.next_history]
-    return result
-  end
-end
-
-function redo_event(State)
-  if State.next_history <= #State.history then
---?     print('restoring history', State.next_history+1)
-    local result = State.history[State.next_history]
-    State.next_history = State.next_history+1
-    return result
-  end
-end
-
--- Copy all relevant global state.
--- Make copies of objects; the rest of the app may mutate them in place, but undo requires immutable histories.
-function snapshot(State, s,e)
-  -- Snapshot everything by default, but subset if requested.
-  assert(s, 'failed to snapshot operation for undo history')
-  if e == nil then
-    e = s
-  end
-  assert(#State.lines > 0, 'failed to snapshot operation for undo history')
-  if s < 1 then s = 1 end
-  if s > #State.lines then s = #State.lines end
-  if e < 1 then e = 1 end
-  if e > #State.lines then e = #State.lines end
-  -- compare with App.initialize_globals
-  local event = {
-    screen_top=deepcopy(State.screen_top1),
-    selection=deepcopy(State.selection1),
-    cursor=deepcopy(State.cursor1),
-    lines={},
-    start_line=s,
-    end_line=e,
-    -- no filename; undo history is cleared when filename changes
-  }
-  for i=s,e do
-    table.insert(event.lines, deepcopy(State.lines[i]))
-  end
-  return event
-end
-
-function patch(lines, from, to)
---?   if #from.lines == 1 and #to.lines == 1 then
---?     assert(from.start_line == from.end_line)
---?     assert(to.start_line == to.end_line)
---?     assert(from.start_line == to.start_line)
---?     lines[from.start_line] = to.lines[1]
---?     return
---?   end
-  assert(from.start_line == to.start_line, 'failed to patch undo operation')
-  for i=from.end_line,from.start_line,-1 do
-    table.remove(lines, i)
-  end
-  assert(#to.lines == to.end_line-to.start_line+1, 'failed to patch undo operation')
-  for i=1,#to.lines do
-    table.insert(lines, to.start_line+i-1, to.lines[i])
-  end
-end
-
 -- https://stackoverflow.com/questions/640642/how-do-you-copy-a-lua-table-by-value/26367080#26367080
 function deepcopy(obj, seen)
   if type(obj) ~= 'table' then return obj end
-  if seen and seen[obj] then return seen[obj] end
-  local s = seen or {}
+  seen = seen or {}
+  if seen[obj] then return seen[obj] end
   local result = setmetatable({}, getmetatable(obj))
-  s[obj] = result
+  seen[obj] = result
   for k,v in pairs(obj) do
-    result[deepcopy(k, s)] = deepcopy(v, s)
+    result[deepcopy(k, seen)] = deepcopy(v, seen)
   end
   return result
 end
generated by cgit-pink 1.4.1-2-gfad0 (git 2.36.2.497.gbbea4dcf42) at 2025-07-06 12:40:02 +0000