break.tlv: nascent live-updating stack language

Joint work with Sumeet Agarwal. In the process we discovered several
bugs in our fake window helpers for tests. Thanks Sumeet!

Previous prototypes:
  - https://archive.org/details/akkartik-2min-2020-12-06
  - https://merveilles.town/@akkartik/105759816342173743

6 files changed, 824 insertions, 12 deletions

diff --git a/anagrams.tlv b/anagrams.tlv
index a314eb8..70ef124 100644
--- a/anagrams.tlv
+++ b/anagrams.tlv
@@ -104,6 +104,8 @@
     >    end
     >    result = result..'}'
     >    return result
+    >  elseif type(x) == 'string' then
+    >    return '"'..x..'"'
     >  end
     >  return tostring(x)
     >end
diff --git a/break.tlv b/break.tlv
new file mode 100644
index 0000000..8f06963
--- /dev/null
+++ b/break.tlv
@@ -0,0 +1,766 @@
+# .tlv file generated by https://github.com/akkartik/teliva
+# You may edit it if you are careful; however, you may see cryptic errors if you
+# violate Teliva's assumptions.
+#
+# .tlv files are representations of Teliva programs. Teliva programs consist of
+# sequences of definitions. Each definition is a table of key/value pairs. Keys
+# and values are both strings.
+#
+# Lines in .tlv files always follow exactly one of the following forms:
+# - comment lines at the top of the file starting with '#' at column 0
+# - beginnings of definitions starting with '- ' at column 0, followed by a
+#   key/value pair
+# - key/value pairs consisting of '  ' at column 0, containing either a
+#   spaceless value on the same line, or a multi-line value
+# - multiline values indented by more than 2 spaces, starting with a '>'
+#
+# If these constraints are violated, Teliva may unceremoniously crash. Please
+# report bugs at http://akkartik.name/contact
+- __teliva_timestamp: original
+  str_helpers:
+    >-- some string helpers from http://lua-users.org/wiki/StringIndexing
+    >
+    >-- index characters using []
+    >getmetatable('').__index = function(str,i)
+    >  if type(i) == 'number' then
+    >    return str:sub(i,i)
+    >  else
+    >    return string[i]
+    >  end
+    >end
+    >
+    >-- ranges using (), selected bytes using {}
+    >getmetatable('').__call = function(str,i,j)
+    >  if type(i)~='table' then
+    >    return str:sub(i,j)
+    >  else
+    >    local t={}
+    >    for k,v in ipairs(i) do
+    >      t[k]=str:sub(v,v)
+    >    end
+    >    return table.concat(t)
+    >  end
+    >end
+    >
+    >-- iterate over an ordered sequence
+    >function q(x)
+    >  if type(x) == 'string' then
+    >    return x:gmatch('.')
+    >  else
+    >    return ipairs(x)
+    >  end
+    >end
+    >
+    >-- insert within string
+    >function string.insert(str1, str2, pos)
+    >  return str1:sub(1,pos)..str2..str1:sub(pos+1)
+    >end
+    >
+    >function string.remove(s, pos)
+    >  return s:sub(1,pos-1)..s:sub(pos+1)
+    >end
+    >
+    >-- TODO: backport utf-8 support from Lua 5.3
+- __teliva_timestamp: original
+  debugy:
+    >debugy = 5
+- __teliva_timestamp: original
+  dbg:
+    >-- helper for debug by print; overlay debug information towards the right
+    >-- reset debugy every time you refresh screen
+    >function dbg(window, s)
+    >  local oldy = 0
+    >  local oldx = 0
+    >  oldy, oldx = window:getyx()
+    >  window:mvaddstr(debugy, 60, s)
+    >  debugy = debugy+1
+    >  window:mvaddstr(oldy, oldx, '')
+    >end
+- __teliva_timestamp: original
+  check:
+    >function check(x, msg)
+    >  if x then
+    >    Window:addch('.')
+    >  else
+    >    print('F - '..msg)
+    >    print('  '..str(x)..' is false/nil')
+    >    teliva_num_test_failures = teliva_num_test_failures + 1
+    >    -- overlay first test failure on editors
+    >    if teliva_first_failure == nil then
+    >      teliva_first_failure = msg
+    >    end
+    >  end
+    >end
+- __teliva_timestamp: original
+  check_eq:
+    >function check_eq(x, expected, msg)
+    >  if eq(x, expected) then
+    >    Window:addch('.')
+    >  else
+    >    print('F - '..msg)
+    >    print('  expected '..str(expected)..' but got '..str(x))
+    >    teliva_num_test_failures = teliva_num_test_failures + 1
+    >    -- overlay first test failure on editors
+    >    if teliva_first_failure == nil then
+    >      teliva_first_failure = msg
+    >    end
+    >  end
+    >end
+- __teliva_timestamp: original
+  eq:
+    >function eq(a, b)
+    >  if type(a) ~= type(b) then return false end
+    >  if type(a) == 'table' then
+    >    if #a ~= #b then return false end
+    >    for k, v in pairs(a) do
+    >      if b[k] ~= v then
+    >        return false
+    >      end
+    >      return true
+    >    end
+    >  end
+    >  return a == b
+    >end
+- __teliva_timestamp: original
+  str:
+    >-- smarter tostring
+    >-- slow; used only for debugging
+    >function str(x)
+    >  if type(x) == 'table' then
+    >    local result = ''
+    >    result = result..#x..'{'
+    >    for k, v in pairs(x) do
+    >      result = result..str(k)..'='..str(v)..', '
+    >    end
+    >    result = result..'}'
+    >    return result
+    >  elseif type(x) == 'string' then
+    >    return '"'..x..'"'
+    >  end
+    >  return tostring(x)
+    >end
+- __teliva_timestamp: original
+  map:
+    >-- only for arrays
+    >function map(l, f)
+    >  result = {}
+    >  for _, x in ipairs(l) do
+    >    table.insert(result, f(x))
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp: original
+  reduce:
+    >-- only for arrays
+    >function reduce(l, f, init)
+    >  result = init
+    >  for _, x in ipairs(l) do
+    >    result = f(result, x)
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp: original
+  filter:
+    >-- only for arrays
+    >function filter(l, f)
+    >  result = {}
+    >  for _, x in ipairs(l) do
+    >    if f(x) then
+    >      table.insert(result, x)
+    >    end
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp: original
+  find_index:
+    >function find_index(arr, x)
+    >  for n, y in ipairs(arr) do
+    >    if x == y then
+    >      return n
+    >    end
+    >  end
+    >end
+- __teliva_timestamp: original
+  trim:
+    >function trim(s)
+    >  return s:gsub('^%s*', ''):gsub('%s*$', '')
+    >end
+- __teliva_timestamp: original
+  split:
+    >function split(s, d)
+    >  result = {}
+    >  for match in (s..d):gmatch("(.-)"..d) do
+    >    table.insert(result, match);
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp: original
+  sort_letters:
+    >function sort_letters(s)
+    >  tmp = {}
+    >  for i=1,#s do
+    >    table.insert(tmp, s[i])
+    >  end
+    >  table.sort(tmp)
+    >  local result = ''
+    >  for _, c in pairs(tmp) do
+    >    result = result..c
+    >  end
+    >  return result
+    >end
+    >
+    >function test_sort_letters(s)
+    >  check_eq(sort_letters(''), '', 'test_sort_letters: empty')
+    >  check_eq(sort_letters('ba'), 'ab', 'test_sort_letters: non-empty')
+    >  check_eq(sort_letters('abba'), 'aabb', 'test_sort_letters: duplicates')
+    >end
+- __teliva_timestamp: original
+  count_letters:
+    >function count_letters(s)
+    >  local result = {}
+    >  for i=1,s:len() do
+    >    local c = s[i]
+    >    if result[c] == nil then
+    >      result[c] = 1
+    >    else
+    >      result[c] = result[c] + 1
+    >    end
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp: original
+  append:
+    >-- concatenate list 'elems' into 'l', modifying 'l' in the process
+    >function append(l, elems)
+    >  for i=1,#elems do
+    >    l[#l+1] = elems[i]
+    >  end
+    >end
+- __teliva_timestamp: original
+  menu:
+    >-- To show app-specific hotkeys in the menu bar, add hotkey/command
+    >-- arrays of strings to the menu array.
+    >menu = {}
+- __teliva_timestamp: original
+  Window:
+    >Window = curses.stdscr()
+- __teliva_timestamp: original
+  window:
+    >-- constructor for fake screen and window
+    >-- call it like this:
+    >--   local w = window{
+    >--     kbd=kbd('abc'),
+    >--     scr=scr{h=5, w=4},
+    >--   }
+    >-- eventually it'll do everything a real ncurses window can
+    >function window(h)
+    >  h.__index = h
+    >  setmetatable(h, h)
+    >  h.__index = function(table, key)
+    >    return rawget(h, key)
+    >  end
+    >  h.attrset = function(self, x)
+    >    self.scr.attrs = x
+    >  end
+    >  h.attron = function(self, x)
+    >    -- currently same as attrset since Lua 5.1 doesn't have bitwise operators
+    >    -- doesn't support multiple attrs at once
+    >--    local old = self.scr.attrs
+    >--    self.scr.attrs = old|x
+    >    self.scr.attrs = x
+    >  end
+    >  h.attroff = function(self, x)
+    >    -- currently borked since Lua 5.1 doesn't have bitwise operators
+    >    -- doesn't support multiple attrs at once
+    >--    local old = self.scr.attrs
+    >--    self.scr.attrs = old & (~x)
+    >    self.scr.attrs = curses.A_NORMAL
+    >  end
+    >  h.getch = function(self)
+    >    local c = table.remove(h.kbd, 1)
+    >    if c == nil then return c end
+    >    return string.byte(c)  -- for verisimilitude with ncurses
+    >  end
+    >  h.addch = function(self, c)
+    >    local scr = self.scr
+    >    if c == '\n' then
+    >      scr.cursy = scr.cursy+1
+    >      scr.cursx = 0
+    >      return
+    >    end
+    >    if scr.cursy <= scr.h then
+    >      scr[scr.cursy][scr.cursx] = {data=c, attrs=scr.attrs}
+    >      scr.cursx = scr.cursx+1
+    >      if scr.cursx > scr.w then
+    >        scr.cursy = scr.cursy+1
+    >        scr.cursx = 1
+    >      end
+    >    end
+    >  end
+    >  h.addstr = function(self, s)
+    >    for i=1,s:len() do
+    >      self:addch(s[i])
+    >    end
+    >  end
+    >  h.mvaddch = function(self, y, x, c)
+    >    self.scr.cursy = y
+    >    self.scr.cursx = x
+    >    self:addch(c)
+    >  end
+    >  h.mvaddstr = function(self, y, x, s)
+    >    self.scr.cursy = y
+    >    self.scr.cursx = x
+    >    self:addstr(s)
+    >  end
+    >  h.clear = function(self)
+    >    clear_scr(self.scr)
+    >  end
+    >  h.refresh = function(self)
+    >    -- nothing
+    >  end
+    >  return h
+    >end
+- __teliva_timestamp: original
+  kbd:
+    >function kbd(keys)
+    >  local result = {}
+    >  for i=1,keys:len() do
+    >    table.insert(result, keys[i])
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp: original
+  scr:
+    >function scr(props)
+    >  props.cursx = 1
+    >  props.cursy = 1
+    >  clear_scr(props)
+    >  return props
+    >end
+- __teliva_timestamp: original
+  clear_scr:
+    >function clear_scr(props)
+    >  props.cursy = 1
+    >  props.cursx = 1
+    >  for y=1,props.h do
+    >    props[y] = {}
+    >    for x=1,props.w do
+    >      props[y][x] = {data=' ', attrs=curses.A_NORMAL}
+    >    end
+    >  end
+    >  return props
+    >end
+- __teliva_timestamp: original
+  check_screen:
+    >function check_screen(window, contents, message)
+    >  local x, y = 1, 1
+    >  for i=1,contents:len() do
+    >    check_eq(window.scr[y][x].data, contents[i], message..'/'..y..','..x)
+    >    x = x+1
+    >    if x > window.scr.w then
+    >      y = y+1
+    >      x = 1
+    >    end
+    >  end
+    >end
+    >
+    >-- putting it all together, an example test of both keyboard and screen
+    >function test_check_screen()
+    >  local lines = {
+    >    c='123',
+    >    d='234',
+    >    a='345',
+    >    b='456',
+    >  }
+    >  local w = window{
+    >    kbd=kbd('abc'),
+    >    scr=scr{h=3, w=5},
+    >  }
+    >  local y = 1
+    >  while true do
+    >    local b = w:getch()
+    >    if b == nil then break end
+    >    w:mvaddstr(y, 1, lines[string.char(b)])
+    >    y = y+1
+    >  end
+    >  check_screen(w, '345  '..
+    >                  '456  '..
+    >                  '123  ',
+    >              'test_check_screen')
+    >end
+- __teliva_timestamp: original
+  check_reverse:
+    >function check_reverse(window, contents, message)
+    >  local x, y = 1, 1
+    >  for i=1,contents:len() do
+    >    if contents[i] ~= ' ' then
+    >      -- hacky version while we're without bitwise operators on Lua 5.1
+    >--      check(window.scr[y][x].attrs & curses.A_REVERSE, message..'/'..y..','..x)
+    >      check_eq(window.scr[y][x].attrs, curses.A_REVERSE, message..'/'..y..','..x)
+    >    else
+    >      -- hacky version while we're without bitwise operators on Lua 5.1
+    >--      check(window.scr[y][x].attrs & (~curses.A_REVERSE), message..'/'..y..','..x)
+    >      check(window.scr[y][x].attrs ~= curses.A_REVERSE, message..'/'..y..','..x)
+    >    end
+    >    x = x+1
+    >    if x > window.scr.w then
+    >      y = y+1
+    >      x = 1
+    >    end
+    >  end
+    >end
+- __teliva_timestamp: original
+  check_bold:
+    >function check_bold(window, contents, message)
+    >  local x, y = 1, 1
+    >  for i=1,contents:len() do
+    >    if contents[i] ~= ' ' then
+    >      -- hacky version while we're without bitwise operators on Lua 5.1
+    >--      check(window.scr[y][x].attrs & curses.A_BOLD, message..'/'..y..','..x)
+    >      check_eq(window.scr[y][x].attrs, curses.A_BOLD, message..'/'..y..','..x)
+    >    else
+    >      -- hacky version while we're without bitwise operators on Lua 5.1
+    >--      check(window.scr[y][x].attrs & (~curses.A_BOLD), message..'/'..y..','..x)
+    >      check(window.scr[y][x].attrs ~= curses.A_BOLD, message..'/'..y..','..x)
+    >    end
+    >    x = x+1
+    >    if x > window.scr.w then
+    >      y = y+1
+    >      x = 1
+    >    end
+    >  end
+    >end
+- __teliva_timestamp: original
+  check_color:
+    >-- check which parts of a screen have the given color_pair
+    >function check_color(window, cp, contents, message)
+    >  local x, y = 1, 1
+    >  for i=1,contents:len() do
+    >    if contents[i] ~= ' ' then
+    >      -- hacky version while we're without bitwise operators on Lua 5.1
+    >--      check(window.scr[y][x].attrs & curses.color_pair(cp), message..'/'..y..','..x)
+    >      check_eq(window.scr[y][x].attrs, curses.color_pair(cp), message..'/'..y..','..x)
+    >    else
+    >      -- hacky version while we're without bitwise operators on Lua 5.1
+    >--      check(window.scr[y][x].attrs & (~curses.A_BOLD), message..'/'..y..','..x)
+    >      check(window.scr[y][x].attrs ~= curses.color_pair(cp), message..'/'..y..','..x)
+    >    end
+    >    x = x+1
+    >    if x > window.scr.w then
+    >      y = y+1
+    >      x = 1
+    >    end
+    >  end
+    >end
+- __teliva_timestamp: original
+  render:
+    >function render(window)
+    >  window:clear()
+    >  -- draw stuff to screen here
+    >  window:attron(curses.A_BOLD)
+    >  window:mvaddstr(1, 5, "example app")
+    >  window:attrset(curses.A_NORMAL)
+    >  for i=0,15 do
+    >    window:attrset(curses.color_pair(i))
+    >    window:mvaddstr(3+i, 5, "========================")
+    >  end
+    >  window:refresh()
+    >end
+- __teliva_timestamp: original
+  update:
+    >function update(window)
+    >  local key = window:getch()
+    >  -- process key here
+    >end
+- __teliva_timestamp: original
+  init_colors:
+    >function init_colors()
+    >  for i=0,7 do
+    >    curses.init_pair(i, i, -1)
+    >  end
+    >  curses.init_pair(8, 7, 0)
+    >  curses.init_pair(9, 7, 1)
+    >  curses.init_pair(10, 7, 2)
+    >  curses.init_pair(11, 7, 3)
+    >  curses.init_pair(12, 7, 4)
+    >  curses.init_pair(13, 7, 5)
+    >  curses.init_pair(14, 7, 6)
+    >  curses.init_pair(15, -1, 15)
+    >end
+- __teliva_timestamp: original
+  main:
+    >function main()
+    >  init_colors()
+    >
+    >  while true do
+    >    render(Window)
+    >    update(Window)
+    >  end
+    >end
+- __teliva_timestamp:
+    >Thu Mar 17 21:21:29 2022
+  program:
+    >program = {lines = nil, cursor = nil}
+    >-- lines: [line]
+    >-- cursor: int, index into lines
+    >-- line: {[word], cursor}
+    >-- word: {string, cursor}
+- __teliva_timestamp:
+    >Thu Mar 17 21:27:38 2022
+  render:
+    >function render(window)
+    >  local key = window:getch()
+    >  for row, line in ipair(program.lines) do
+    >    for col, word in ipair(line.words) do
+    >      window:addstr(word)
+    >      window:addstr(' ')
+    >    end
+    >    window:addstr('\n')
+    >  end
+    >end
+- __teliva_timestamp:
+    >Thu Mar 17 21:28:39 2022
+  render:
+    >function render(window)
+    >  local key = window:getch()
+    >  for row, line in ipairs(program.lines) do
+    >    for col, word in pairs(line.words) do
+    >      window:addstr(word)
+    >      window:addstr(' ')
+    >    end
+    >    window:addstr('\n')
+    >  end
+    >end
+- __teliva_timestamp:
+    >Thu Mar 17 21:31:33 2022
+  Program:
+    >Program = {
+    >  cursor_y = 1,
+    >  lines = {
+    >    {
+    >      cursor_x = 1,
+    >      words = {
+    >        {
+    >          cursor = 0,
+    >          data = '',
+    >        },
+    >      },
+    >    },
+    >  },
+    >}
+    >
+    >
+    >
+    >
+    >
+- __teliva_timestamp:
+    >Thu Mar 17 21:32:05 2022
+  render:
+    >function render(window)
+    >  window:clear()
+    >  for row, line in ipairs(program.lines) do
+    >    for col, word in pairs(line.words) do
+    >      window:addstr(word)
+    >      window:addstr(' ')
+    >    end
+    >    window:addstr('\n')
+    >  end
+    >  window:refresh()
+    >end
+- __teliva_timestamp:
+    >Thu Mar 17 21:32:22 2022
+  render:
+    >function render(window)
+    >  window:clear()
+    >  for row, line in ipairs(program.lines) do
+    >    for col, word in pairs(line.words) do
+    >      window:addstr(word.data)
+    >      window:addstr(' ')
+    >    end
+    >    window:addstr('\n')
+    >  end
+    >  window:refresh()
+    >end
+- __teliva_timestamp:
+    >Thu Mar 17 21:33:00 2022
+  update:
+    >function update(window)
+    >  local key = window:getch()
+    >  if key == ' ' then
+    >    print('space')
+    >    window:getch()
+    >  end
+    >end
+- __teliva_timestamp:
+    >Thu Mar 17 21:33:17 2022
+  update:
+    >function update(window)
+    >  local key = window:getch()
+    >  if key == string.byte(' ') then
+    >    print('space')
+    >    window:getch()
+    >  end
+    >end
+- __teliva_timestamp:
+    >Thu Mar 17 21:33:31 2022
+  update:
+    >function update(window)
+    >  local key = string.char(window:getch())
+    >  if key == ' ' then
+    >    print('space')
+    >    window:getch()
+    >  end
+    >end
+- __teliva_timestamp:
+    >Thu Mar 17 21:36:14 2022
+  __teliva_note:
+    >very initial skeleton
+    >- just render, no eval
+    >- no stack rendering
+    >- no cursor (just appends)
+  update:
+    >function update(window)
+    >  local key = string.char(window:getch())
+    >  local nwords = #program.lines[1].words
+    >  if key == ' ' then
+    >    program.lines[1].words[nwords+1] = {data='', cursor=0}
+    >  else
+    >    program.lines[1].words[nwords].data = program.lines[1].words[nwords].data .. key
+    >  end
+    >end
+- __teliva_timestamp:
+    >Thu Mar 17 21:39:24 2022
+  main:
+    >function main()
+    >  init_colors()
+    >
+    >  while true do
+    >    render(Window)
+    >    update(Window)
+    >  end
+    >end
+    >
+    >function test_basic_render()
+    >  
+- __teliva_timestamp:
+    >Thu Mar 17 21:43:05 2022
+  main:
+    >function main()
+    >  init_colors()
+    >
+    >  while true do
+    >    render(Window, Program)
+    >    update(Window, Program)
+    >  end
+    >end
+- __teliva_timestamp:
+    >Thu Mar 17 21:43:11 2022
+  render:
+    >function render(window, program)
+    >  window:clear()
+    >  for row, line in ipairs(program.lines) do
+    >    for col, word in pairs(line.words) do
+    >      window:addstr(word.data)
+    >      window:addstr(' ')
+    >    end
+    >    window:addstr('\n')
+    >  end
+    >  window:refresh()
+    >end
+    >
+    >function test_render()
+    >  local w = window{
+    >    kbd=kbd(''),
+    >    scr=scr{h=3, w=5},
+    >  }
+    >end
+- __teliva_timestamp:
+    >Thu Mar 17 21:43:20 2022
+  update:
+    >function update(window, program, key)
+    >  local nwords = #program.lines[1].words
+    >  if key == ' ' then
+    >    program.lines[1].words[nwords+1] = {data='', cursor=0}
+    >  else
+    >    program.lines[1].words[nwords].data = program.lines[1].words[nwords].data .. key
+    >  end
+    >end
+- __teliva_timestamp:
+    >Thu Mar 17 21:58:10 2022
+  Program:
+    >Program = empty_program()
+- __teliva_timestamp:
+    >Thu Mar 17 21:58:10 2022
+  empty_program:
+    >function empty_program()
+    >  return {
+    >    cursor_y = 1,
+    >    lines = {
+    >      {
+    >        cursor_x = 1,
+    >        words = {
+    >          {
+    >            cursor = 0,
+    >            data = '',
+    >          },
+    >        },
+    >      },
+    >    },
+    >  }
+    >end
+- __teliva_timestamp:
+    >Thu Mar 17 22:36:24 2022
+  render:
+    >function render(window, program)
+    >  window:clear()
+    >  for row, line in ipairs(program.lines) do
+    >    for col, word in pairs(line.words) do
+    >      window:addstr(word.data)
+    >      window:addstr(' ')
+    >    end
+    >    window:addstr('\n')
+    >  end
+    >  window:refresh()
+    >end
+- __teliva_timestamp:
+    >Thu Mar 17 22:41:01 2022
+  __teliva_note:
+    >a passing test
+  main:
+    >function main()
+    >  init_colors()
+    >
+    >  while true do
+    >    render(Window, Program)
+    >    local key = string.char(Window:getch())  -- nodelay can't be set
+    >    update(Window, Program, key)
+    >  end
+    >end
+    >
+    >function test_incomplete()
+    >  local w = window{
+    >    kbd=kbd('ab c'),
+    >    scr=scr{h=3, w=5},
+    >  }
+    >  local prog = empty_program()
+    >  while true do
+    >    render(w, prog)
+    >    local key = w:getch()
+    >    if key == nil then break end
+    >    update(w, prog, string.char(key))
+    >  end
+    >  check_screen(w, 'ab c '..
+    >                  '     '..
+    >                  '     ',
+    >               'test_main_incomplete')
+    >end
+- __teliva_timestamp: original
+  doc:blurb:
+    >A concatenative programming language with a live-updating debug UI.
+    >by Kartik Agaram and Sumeet Agarwal
+    >
+    >Highly incomplete.
+    >
+    >Previous prototypes:
+    >  - https://archive.org/details/akkartik-2min-2020-12-06
+    >  - https://merveilles.town/@akkartik/105759816342173743
diff --git a/life.tlv b/life.tlv
index 6c62f31..836c5f3 100644
--- a/life.tlv
+++ b/life.tlv
@@ -134,6 +134,8 @@
     >    end
     >    result = result..'}'
     >    return result
+    >  elseif type(x) == 'string' then
+    >    return '"'..x..'"'
     >  end
     >  return tostring(x)
     >end
@@ -272,10 +274,17 @@
     >    self.scr.attrs = curses.A_NORMAL
     >  end
     >  h.getch = function(self)
-    >    return table.remove(h.kbd, 1)
+    >    local c = table.remove(h.kbd, 1)
+    >    if c == nil then return c end
+    >    return string.byte(c)  -- for verisimilitude with ncurses
     >  end
     >  h.addch = function(self, c)
     >    local scr = self.scr
+    >    if c == '\n' then
+    >      scr.cursy = scr.cursy+1
+    >      scr.cursx = 0
+    >      return
+    >    end
     >    if scr.cursy <= scr.h then
     >      scr[scr.cursy][scr.cursx] = {data=c, attrs=scr.attrs}
     >      scr.cursx = scr.cursx+1
@@ -303,6 +312,9 @@
     >  h.clear = function(self)
     >    clear_scr(self.scr)
     >  end
+    >  h.refresh = function(self)
+    >    -- nothing
+    >  end
     >  return h
     >end
 - __teliva_timestamp: original
@@ -325,6 +337,8 @@
 - __teliva_timestamp: original
   clear_scr:
     >function clear_scr(props)
+    >  props.cursy = 1
+    >  props.cursx = 1
     >  for y=1,props.h do
     >    props[y] = {}
     >    for x=1,props.w do
@@ -361,9 +375,9 @@
     >  }
     >  local y = 1
     >  while true do
-    >    local c = w:getch()
-    >    if c == nil then break end
-    >    w:mvaddstr(y, 1, lines[c])
+    >    local b = w:getch()
+    >    if b == nil then break end
+    >    w:mvaddstr(y, 1, lines[string.char(b)])
     >    y = y+1
     >  end
     >  check_screen(w, '345  '..
diff --git a/template.tlv b/template.tlv
index 31fa6b4..2387368 100644
--- a/template.tlv
+++ b/template.tlv
@@ -134,6 +134,8 @@
     >    end
     >    result = result..'}'
     >    return result
+    >  elseif type(x) == 'string' then
+    >    return '"'..x..'"'
     >  end
     >  return tostring(x)
     >end
@@ -275,10 +277,17 @@
     >    self.scr.attrs = curses.A_NORMAL
     >  end
     >  h.getch = function(self)
-    >    return table.remove(h.kbd, 1)
+    >    local c = table.remove(h.kbd, 1)
+    >    if c == nil then return c end
+    >    return string.byte(c)  -- for verisimilitude with ncurses
     >  end
     >  h.addch = function(self, c)
     >    local scr = self.scr
+    >    if c == '\n' then
+    >      scr.cursy = scr.cursy+1
+    >      scr.cursx = 0
+    >      return
+    >    end
     >    if scr.cursy <= scr.h then
     >      scr[scr.cursy][scr.cursx] = {data=c, attrs=scr.attrs}
     >      scr.cursx = scr.cursx+1
@@ -306,6 +315,9 @@
     >  h.clear = function(self)
     >    clear_scr(self.scr)
     >  end
+    >  h.refresh = function(self)
+    >    -- nothing
+    >  end
     >  return h
     >end
 - __teliva_timestamp: original
@@ -328,6 +340,8 @@
 - __teliva_timestamp: original
   clear_scr:
     >function clear_scr(props)
+    >  props.cursy = 1
+    >  props.cursx = 1
     >  for y=1,props.h do
     >    props[y] = {}
     >    for x=1,props.w do
@@ -364,9 +378,9 @@
     >  }
     >  local y = 1
     >  while true do
-    >    local c = w:getch()
-    >    if c == nil then break end
-    >    w:mvaddstr(y, 1, lines[c])
+    >    local b = w:getch()
+    >    if b == nil then break end
+    >    w:mvaddstr(y, 1, lines[string.char(b)])
     >    y = y+1
     >  end
     >  check_screen(w, '345  '..
diff --git a/toot-toot.tlv b/toot-toot.tlv
index 35d8b15..8f224c4 100644
--- a/toot-toot.tlv
+++ b/toot-toot.tlv
@@ -119,6 +119,8 @@
     >    end
     >    result = result..'}'
     >    return result
+    >  elseif type(x) == 'string' then
+    >    return '"'..x..'"'
     >  end
     >  return tostring(x)
     >end
diff --git a/zet.tlv b/zet.tlv
index ab0ad79..184cf92 100644
--- a/zet.tlv
+++ b/zet.tlv
@@ -134,6 +134,8 @@
     >    end
     >    result = result..'}'
     >    return result
+    >  elseif type(x) == 'string' then
+    >    return '"'..x..'"'
     >  end
     >  return tostring(x)
     >end
@@ -277,10 +279,17 @@
     >    self.scr.attrs = curses.A_NORMAL
     >  end
     >  h.getch = function(self)
-    >    return table.remove(h.kbd, 1)
+    >    local c = table.remove(h.kbd, 1)
+    >    if c == nil then return c end
+    >    return string.byte(c)  -- for verisimilitude with ncurses
     >  end
     >  h.addch = function(self, c)
     >    local scr = self.scr
+    >    if c == '\n' then
+    >      scr.cursy = scr.cursy+1
+    >      scr.cursx = 0
+    >      return
+    >    end
     >    if scr.cursy <= scr.h then
     >      scr[scr.cursy][scr.cursx] = {data=c, attrs=scr.attrs}
     >      scr.cursx = scr.cursx+1
@@ -308,6 +317,9 @@
     >  h.clear = function(self)
     >    clear_scr(self.scr)
     >  end
+    >  h.refresh = function(self)
+    >    -- nothing
+    >  end
     >  return h
     >end
 - __teliva_timestamp: original
@@ -330,6 +342,8 @@
 - __teliva_timestamp: original
   clear_scr:
     >function clear_scr(props)
+    >  props.cursy = 1
+    >  props.cursx = 1
     >  for y=1,props.h do
     >    props[y] = {}
     >    for x=1,props.w do
@@ -366,9 +380,9 @@
     >  }
     >  local y = 1
     >  while true do
-    >    local c = w:getch()
-    >    if c == nil then break end
-    >    w:mvaddstr(y, 1, lines[c])
+    >    local b = w:getch()
+    >    if b == nil then break end
+    >    w:mvaddstr(y, 1, lines[string.char(b)])
     >    y = y+1
     >  end
     >  check_screen(w, '345  '..