snapshot: migrate all sample apps to new format

1 files changed, 308 insertions, 342 deletions

diff --git a/life.tlv b/life.tlv
index ba4f1e7..2abfd08 100644
--- a/life.tlv
+++ b/life.tlv
@@ -1,342 +1,308 @@
-teliva_program = {
-  {
-    __teliva_timestamp = [==[
-original]==],
-    grid = [==[
--- main data structure
-grid = {}
-for i=1,lines*4 do
-  grid[i] = {}
-  for j=1,cols*2 do
-    grid[i][j] = 0
-  end
-end
-]==],
-  },
-  {
-    __teliva_timestamp = [==[
-original]==],
-    window = [==[
-window = curses.stdscr()
--- animation-based app
-window:nodelay(true)
-lines, cols = window:getmaxyx()]==],
-  },
-  {
-    __teliva_timestamp = [==[
-original]==],
-    grid_char = [==[
--- grab a 4x2 chunk of grid
-function grid_char(line, col)
-  result = {}
-  for l, row in ipairs({unpack(grid, (line-1)*4+1, line*4)}) do
-    result[l] = {unpack(row, (col-1)*2+1, col*2)}
-  end
-  return result
-end]==],
-  },
-  {
-    __teliva_timestamp = [==[
-original]==],
-    print_grid_char = [==[
-function print_grid_char(window, x)
-  result = {}
-  for l, row in ipairs(x) do
-    for c, val in ipairs(row) do
-      window:mvaddstr(l, c, val)
-    end
-  end
-  return result
-end]==],
-  },
-  {
-    __teliva_timestamp = [==[
-original]==],
-    glyph = [==[
--- look up the braille pattern corresponding to a 4x2 chunk of grid
--- https://en.wikipedia.org/wiki/Braille_Patterns
--- not obviously programmatic because Unicode added 4x2 after 3x2
-glyph = {
-  0x2800, 0x2801, 0x2802, 0x2803, 0x2804, 0x2805, 0x2806, 0x2807,   0x2840, 0x2841, 0x2842, 0x2843, 0x2844, 0x2845, 0x2846, 0x2847,
-  0x2808, 0x2809, 0x280a, 0x280b, 0x280c, 0x280d, 0x280e, 0x280f,   0x2848, 0x2849, 0x284a, 0x284b, 0x284c, 0x284d, 0x284e, 0x284f,
-  0x2810, 0x2811, 0x2812, 0x2813, 0x2814, 0x2815, 0x2816, 0x2817,   0x2850, 0x2851, 0x2852, 0x2853, 0x2854, 0x2855, 0x2856, 0x2857,
-  0x2818, 0x2819, 0x281a, 0x281b, 0x281c, 0x281d, 0x281e, 0x281f,   0x2858, 0x2859, 0x285a, 0x285b, 0x285c, 0x285d, 0x285e, 0x285f,
-  0x2820, 0x2821, 0x2822, 0x2823, 0x2824, 0x2825, 0x2826, 0x2827,   0x2860, 0x2861, 0x2862, 0x2863, 0x2864, 0x2865, 0x2866, 0x2867,
-  0x2828, 0x2829, 0x282a, 0x282b, 0x282c, 0x282d, 0x282e, 0x282f,   0x2868, 0x2869, 0x286a, 0x286b, 0x286c, 0x286d, 0x286e, 0x286f,
-  0x2830, 0x2831, 0x2832, 0x2833, 0x2834, 0x2835, 0x2836, 0x2837,   0x2870, 0x2871, 0x2872, 0x2873, 0x2874, 0x2875, 0x2876, 0x2877,
-  0x2838, 0x2839, 0x283a, 0x283b, 0x283c, 0x283d, 0x283e, 0x283f,   0x2878, 0x2879, 0x287a, 0x287b, 0x287c, 0x287d, 0x287e, 0x287f,
-
-  0x2880, 0x2881, 0x2882, 0x2883, 0x2884, 0x2885, 0x2886, 0x2887,   0x28c0, 0x28c1, 0x28c2, 0x28c3, 0x28c4, 0x28c5, 0x28c6, 0x28c7,
-  0x2888, 0x2889, 0x288a, 0x288b, 0x288c, 0x288d, 0x288e, 0x288f,   0x28c8, 0x28c9, 0x28ca, 0x28cb, 0x28cc, 0x28cd, 0x28ce, 0x28cf,
-  0x2890, 0x2891, 0x2892, 0x2893, 0x2894, 0x2895, 0x2896, 0x2897,   0x28d0, 0x28d1, 0x28d2, 0x28d3, 0x28d4, 0x28d5, 0x28d6, 0x28d7,
-  0x2898, 0x2899, 0x289a, 0x289b, 0x289c, 0x289d, 0x289e, 0x289f,   0x28d8, 0x28d9, 0x28da, 0x28db, 0x28dc, 0x28dd, 0x28de, 0x28df,
-  0x28a0, 0x28a1, 0x28a2, 0x28a3, 0x28a4, 0x28a5, 0x28a6, 0x28a7,   0x28e0, 0x28e1, 0x28e2, 0x28e3, 0x28e4, 0x28e5, 0x28e6, 0x28e7,
-  0x28a8, 0x28a9, 0x28aa, 0x28ab, 0x28ac, 0x28ad, 0x28ae, 0x28af,   0x28e8, 0x28e9, 0x28ea, 0x28eb, 0x28ec, 0x28ed, 0x28ee, 0x28ef,
-  0x28b0, 0x28b1, 0x28b2, 0x28b3, 0x28b4, 0x28b5, 0x28b6, 0x28b7,   0x28f0, 0x28f1, 0x28f2, 0x28f3, 0x28f4, 0x28f5, 0x28f6, 0x28f7,
-  0x28b8, 0x28b9, 0x28ba, 0x28bb, 0x28bc, 0x28bd, 0x28be, 0x28bf,   0x28f8, 0x28f9, 0x28fa, 0x28fb, 0x28fc, 0x28fd, 0x28fe, 0x28ff,
-}]==],
-  },
-  {
-    __teliva_timestamp = [==[
-original]==],
-    utf8 = [==[
--- https://stackoverflow.com/questions/7983574/how-to-write-a-unicode-symbol-in-lua
-function utf8(decimal)
-  local bytemarkers = { {0x7FF,192}, {0xFFFF,224}, {0x1FFFFF,240} }
-  if decimal<128 then return string.char(decimal) end
-  local charbytes = {}
-  for bytes,vals in ipairs(bytemarkers) do
-    if decimal<=vals[1] then
-      for b=bytes+1,2,-1 do
-        local mod = decimal%64
-        decimal = (decimal-mod)/64
-        charbytes[b] = string.char(128+mod)
-      end
-      charbytes[1] = string.char(vals[2]+decimal)
-      break
-    end
-  end
-  return table.concat(charbytes)
-end]==],
-  },
-  {
-    __teliva_timestamp = [==[
-original]==],
-    grid_char_to_glyph_index = [==[
--- convert a chunk of grid into a number
-function grid_char_to_glyph_index(g)
-  return g[1][1]    + g[2][1]*2  + g[3][1]*4  + g[4][1]*8 +
-         g[1][2]*16 + g[2][2]*32 + g[3][2]*64 + g[4][2]*128 +
-         1  -- 1-indexing
-end]==],
-  },
-  {
-    __teliva_timestamp = [==[
-original]==],
-    render = [==[
-function render(window)
-  window:clear()
-  curses.attron(curses.color_pair(1))
-  for line=1,lines do
-    for col=1,cols do
-      window:addstr(utf8(glyph[grid_char_to_glyph_index(grid_char(line, col))]))
-    end
-  end
-  curses.attroff(curses.color_pair(1))
-  curses.refresh()
-end
-]==],
-  },
-  {
-    __teliva_timestamp = [==[
-original]==],
-    state = [==[
-function state(line, col)
-  if line < 1 or line > table.getn(grid) or col < 1 or col > table.getn(grid[1]) then
-    return 0
-  end
-  return grid[line][col]
-end]==],
-  },
-  {
-    __teliva_timestamp = [==[
-original]==],
-    num_live_neighbors = [==[
-function num_live_neighbors(line, col)
-  return state(line-1, col-1) + state(line-1, col) + state(line-1, col+1) +
-         state(line,   col-1) +                      state(line,   col+1) +
-         state(line+1, col-1) + state(line+1, col) + state(line+1, col+1)
-end]==],
-  },
-  {
-    __teliva_timestamp = [==[
-original]==],
-    step = [==[
-function step()
-  local new_grid = {}
-  for line=1,table.getn(grid) do
-    new_grid[line] = {}
-    for col=1,table.getn(grid[1]) do
-      local n = num_live_neighbors(line, col)
-      if n == 3 then
-        new_grid[line][col] = 1
-      elseif n == 2 then
-        new_grid[line][col] = grid[line][col]
-      else
-        new_grid[line][col] = 0
-      end
-    end
-  end
-  grid = new_grid
-end]==],
-  },
-  {
-    __teliva_timestamp = [==[
-original]==],
-    sleep = [==[
-function sleep(a)
-    local sec = tonumber(os.clock() + a);
-    while (os.clock() < sec) do
-    end
-end]==],
-  },
-  {
-    __teliva_timestamp = [==[
-original]==],
-    file_exists = [==[
-function file_exists(filename)
-  local f = io.open(filename, "r")
-  if f ~= nil then
-    io.close(f)
-    return true
-  else
-    return false
-  end
-end]==],
-  },
-  {
-    __teliva_timestamp = [==[
-original]==],
-    load_file = [==[
-function load_file(window, filename)
-  io.input(filename)
-  local line_index = lines
-  for line in io.lines() do
-    if line:sub(1,1) ~= '!' then  -- comment; plaintext files can't have whitespace before comments
-      local col_index = cols
-      for c in line:gmatch(".") do
-        if c == '\r' then break end  -- DOS line ending
-        if c == '.' then
-          grid[line_index][col_index] = 0
-        else
-          grid[line_index][col_index] = 1
-        end
-        col_index = col_index+1
-      end
-      line_index = line_index+1
-    end
-  end
-end]==],
-  },
-  {
-    __teliva_timestamp = [==[
-original]==],
-    update = [==[
-menu = {arrow="pan"}
-
-function update(window, c)
-  if c == curses.KEY_LEFT then
-    for i=1,lines*4 do
-      for j=2,cols*2 do
-        grid[i][j-1] = grid[i][j]
-      end
-      grid[i][cols*2] = 0
-    end
-  elseif c == curses.KEY_DOWN then
-    for i=lines*4-1,1,-1 do
-      for j=1,cols*2 do
-        grid[i+1][j] = grid[i][j]
-      end
-    end
-    for j=1,cols*2 do
-      grid[1][j] = 0
-    end
-  elseif c == curses.KEY_UP then
-    for i=2,lines*4 do
-      for j=1,cols*2 do
-        grid[i-1][j] = grid[i][j]
-      end
-    end
-    for j=1,cols*2 do
-      grid[lines*4][j] = 0
-    end
-  elseif c == curses.KEY_RIGHT then
-    for i=1,lines*4 do
-      for j=cols*2-1,1,-1 do
-        grid[i][j+1] = grid[i][j]
-      end
-      grid[i][1] = 0
-    end
-  end
-end]==],
-  },
-  {
-    __teliva_timestamp = [==[
-original]==],
-    main = [==[
-function main()
-  curses.init_pair(255, 15, 1)  -- reserved for Teliva error messages
-  curses.init_pair(1, 22, 189)
-
-  -- initialize grid based on commandline args
-  if (#arg == 0) then
-    -- by default, start from a deterministically random state
-    for i=1,lines*4 do
-      for j=1,cols*2 do
-        grid[i][j] = math.random(0, 1)
-      end
-    end
-  elseif arg[1] == "random" then
-    -- start from a non-deterministically random start state
-    math.randomseed(os.time())
-    for i=1,lines*4 do
-      for j=1,cols*2 do
-        grid[i][j] = math.random(0, 1)
-      end
-    end
-  -- shortcuts for some common patterns
-  elseif arg[1] == "pentomino" then
-    -- https://www.conwaylife.com/wiki/Pentomino
-    grid[83][172] = 1
-    grid[83][173] = 1
-    grid[84][173] = 1
-    grid[84][174] = 1
-    grid[85][173] = 1
-  elseif arg[1] == "glider" then
-    -- https://www.conwaylife.com/wiki/Glider
-    grid[5][4] = 1
-    grid[6][5] = 1
-    grid[7][3] = 1
-    grid[7][4] = 1
-    grid[7][5] = 1
-  elseif arg[1] == "blinker" then
-    -- https://www.conwaylife.com/wiki/Blinker
-    grid[7][3] = 1
-    grid[7][4] = 1
-    grid[7][5] = 1
-  elseif arg[1] == "block" then
-    -- https://www.conwaylife.com/wiki/Block
-    grid[5][4] = 1
-    grid[5][5] = 1
-    grid[6][4] = 1
-    grid[6][5] = 1
-  elseif arg[1] == "loaf" then
-    -- https://www.conwaylife.com/wiki/Loaf
-    grid[5][4] = 1
-    grid[5][5] = 1
-    grid[6][6] = 1
-    grid[7][6] = 1
-    grid[8][5] = 1
-    grid[7][4] = 1
-    grid[6][3] = 1
-  elseif file_exists(arg[1]) then
-    -- Load a file in the standard "plaintext" format: https://www.conwaylife.com/wiki/Plaintext
-    --
-    -- Each pattern page at https://www.conwaylife.com/wiki provides its
-    -- plaintext representation in a block called "Pattern Files" on the right.
-    --
-    -- For example, check out the list of Important Patterns at
-    -- https://www.conwaylife.com/wiki/Category:Patterns_with_Catagolue_frequency_class_0
-    load_file(window, arg[1])
-  end
-
-  -- main loop
-  while true do
-    render(window)
-    c = curses.getch()
-    update(window, c)
-    step()
-  end
-end]==],
-  },
-}
+# .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
+  grid:
+    >-- main data structure
+    >grid = {}
+    >for i=1,lines*4 do
+    >  grid[i] = {}
+    >  for j=1,cols*2 do
+    >    grid[i][j] = 0
+    >  end
+    >end
+- __teliva_timestamp: original
+  window:
+    >window = curses.stdscr()
+    >-- animation-based app
+    >window:nodelay(true)
+    >lines, cols = window:getmaxyx()
+- __teliva_timestamp: original
+  grid_char:
+    >-- grab a 4x2 chunk of grid
+    >function grid_char(line, col)
+    >  result = {}
+    >  for l, row in ipairs({unpack(grid, (line-1)*4+1, line*4)}) do
+    >    result[l] = {unpack(row, (col-1)*2+1, col*2)}
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp: original
+  print_grid_char:
+    >function print_grid_char(window, x)
+    >  result = {}
+    >  for l, row in ipairs(x) do
+    >    for c, val in ipairs(row) do
+    >      window:mvaddstr(l, c, val)
+    >    end
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp: original
+  glyph:
+    >-- look up the braille pattern corresponding to a 4x2 chunk of grid
+    >-- https://en.wikipedia.org/wiki/Braille_Patterns
+    >-- not obviously programmatic because Unicode added 4x2 after 3x2
+    >glyph = {
+    >  0x2800, 0x2801, 0x2802, 0x2803, 0x2804, 0x2805, 0x2806, 0x2807,   0x2840, 0x2841, 0x2842, 0x2843, 0x2844, 0x2845, 0x2846, 0x2847,
+    >  0x2808, 0x2809, 0x280a, 0x280b, 0x280c, 0x280d, 0x280e, 0x280f,   0x2848, 0x2849, 0x284a, 0x284b, 0x284c, 0x284d, 0x284e, 0x284f,
+    >  0x2810, 0x2811, 0x2812, 0x2813, 0x2814, 0x2815, 0x2816, 0x2817,   0x2850, 0x2851, 0x2852, 0x2853, 0x2854, 0x2855, 0x2856, 0x2857,
+    >  0x2818, 0x2819, 0x281a, 0x281b, 0x281c, 0x281d, 0x281e, 0x281f,   0x2858, 0x2859, 0x285a, 0x285b, 0x285c, 0x285d, 0x285e, 0x285f,
+    >  0x2820, 0x2821, 0x2822, 0x2823, 0x2824, 0x2825, 0x2826, 0x2827,   0x2860, 0x2861, 0x2862, 0x2863, 0x2864, 0x2865, 0x2866, 0x2867,
+    >  0x2828, 0x2829, 0x282a, 0x282b, 0x282c, 0x282d, 0x282e, 0x282f,   0x2868, 0x2869, 0x286a, 0x286b, 0x286c, 0x286d, 0x286e, 0x286f,
+    >  0x2830, 0x2831, 0x2832, 0x2833, 0x2834, 0x2835, 0x2836, 0x2837,   0x2870, 0x2871, 0x2872, 0x2873, 0x2874, 0x2875, 0x2876, 0x2877,
+    >  0x2838, 0x2839, 0x283a, 0x283b, 0x283c, 0x283d, 0x283e, 0x283f,   0x2878, 0x2879, 0x287a, 0x287b, 0x287c, 0x287d, 0x287e, 0x287f,
+    >
+    >  0x2880, 0x2881, 0x2882, 0x2883, 0x2884, 0x2885, 0x2886, 0x2887,   0x28c0, 0x28c1, 0x28c2, 0x28c3, 0x28c4, 0x28c5, 0x28c6, 0x28c7,
+    >  0x2888, 0x2889, 0x288a, 0x288b, 0x288c, 0x288d, 0x288e, 0x288f,   0x28c8, 0x28c9, 0x28ca, 0x28cb, 0x28cc, 0x28cd, 0x28ce, 0x28cf,
+    >  0x2890, 0x2891, 0x2892, 0x2893, 0x2894, 0x2895, 0x2896, 0x2897,   0x28d0, 0x28d1, 0x28d2, 0x28d3, 0x28d4, 0x28d5, 0x28d6, 0x28d7,
+    >  0x2898, 0x2899, 0x289a, 0x289b, 0x289c, 0x289d, 0x289e, 0x289f,   0x28d8, 0x28d9, 0x28da, 0x28db, 0x28dc, 0x28dd, 0x28de, 0x28df,
+    >  0x28a0, 0x28a1, 0x28a2, 0x28a3, 0x28a4, 0x28a5, 0x28a6, 0x28a7,   0x28e0, 0x28e1, 0x28e2, 0x28e3, 0x28e4, 0x28e5, 0x28e6, 0x28e7,
+    >  0x28a8, 0x28a9, 0x28aa, 0x28ab, 0x28ac, 0x28ad, 0x28ae, 0x28af,   0x28e8, 0x28e9, 0x28ea, 0x28eb, 0x28ec, 0x28ed, 0x28ee, 0x28ef,
+    >  0x28b0, 0x28b1, 0x28b2, 0x28b3, 0x28b4, 0x28b5, 0x28b6, 0x28b7,   0x28f0, 0x28f1, 0x28f2, 0x28f3, 0x28f4, 0x28f5, 0x28f6, 0x28f7,
+    >  0x28b8, 0x28b9, 0x28ba, 0x28bb, 0x28bc, 0x28bd, 0x28be, 0x28bf,   0x28f8, 0x28f9, 0x28fa, 0x28fb, 0x28fc, 0x28fd, 0x28fe, 0x28ff,
+    >}
+- __teliva_timestamp: original
+  utf8:
+    >-- https://stackoverflow.com/questions/7983574/how-to-write-a-unicode-symbol-in-lua
+    >function utf8(decimal)
+    >  local bytemarkers = { {0x7FF,192}, {0xFFFF,224}, {0x1FFFFF,240} }
+    >  if decimal<128 then return string.char(decimal) end
+    >  local charbytes = {}
+    >  for bytes,vals in ipairs(bytemarkers) do
+    >    if decimal<=vals[1] then
+    >      for b=bytes+1,2,-1 do
+    >        local mod = decimal%64
+    >        decimal = (decimal-mod)/64
+    >        charbytes[b] = string.char(128+mod)
+    >      end
+    >      charbytes[1] = string.char(vals[2]+decimal)
+    >      break
+    >    end
+    >  end
+    >  return table.concat(charbytes)
+    >end
+- __teliva_timestamp: original
+  grid_char_to_glyph_index:
+    >-- convert a chunk of grid into a number
+    >function grid_char_to_glyph_index(g)
+    >  return g[1][1]    + g[2][1]*2  + g[3][1]*4  + g[4][1]*8 +
+    >         g[1][2]*16 + g[2][2]*32 + g[3][2]*64 + g[4][2]*128 +
+    >         1  -- 1-indexing
+    >end
+- __teliva_timestamp: original
+  render:
+    >function render(window)
+    >  window:clear()
+    >  curses.attron(curses.color_pair(1))
+    >  for line=1,lines do
+    >    for col=1,cols do
+    >      window:addstr(utf8(glyph[grid_char_to_glyph_index(grid_char(line, col))]))
+    >    end
+    >  end
+    >  curses.attroff(curses.color_pair(1))
+    >  curses.refresh()
+    >end
+- __teliva_timestamp: original
+  state:
+    >function state(line, col)
+    >  if line < 1 or line > table.getn(grid) or col < 1 or col > table.getn(grid[1]) then
+    >    return 0
+    >  end
+    >  return grid[line][col]
+    >end
+- __teliva_timestamp: original
+  num_live_neighbors:
+    >function num_live_neighbors(line, col)
+    >  return state(line-1, col-1) + state(line-1, col) + state(line-1, col+1) +
+    >         state(line,   col-1) +                      state(line,   col+1) +
+    >         state(line+1, col-1) + state(line+1, col) + state(line+1, col+1)
+    >end
+- __teliva_timestamp: original
+  step:
+    >function step()
+    >  local new_grid = {}
+    >  for line=1,table.getn(grid) do
+    >    new_grid[line] = {}
+    >    for col=1,table.getn(grid[1]) do
+    >      local n = num_live_neighbors(line, col)
+    >      if n == 3 then
+    >        new_grid[line][col] = 1
+    >      elseif n == 2 then
+    >        new_grid[line][col] = grid[line][col]
+    >      else
+    >        new_grid[line][col] = 0
+    >      end
+    >    end
+    >  end
+    >  grid = new_grid
+    >end
+- __teliva_timestamp: original
+  sleep:
+    >function sleep(a)
+    >    local sec = tonumber(os.clock() + a);
+    >    while (os.clock() < sec) do
+    >    end
+    >end
+- __teliva_timestamp: original
+  file_exists:
+    >function file_exists(filename)
+    >  local f = io.open(filename, "r")
+    >  if f ~= nil then
+    >    io.close(f)
+    >    return true
+    >  else
+    >    return false
+    >  end
+    >end
+- __teliva_timestamp: original
+  load_file:
+    >function load_file(window, filename)
+    >  io.input(filename)
+    >  local line_index = lines
+    >  for line in io.lines() do
+    >    if line:sub(1,1) ~= '!' then  -- comment; plaintext files can't have whitespace before comments
+    >      local col_index = cols
+    >      for c in line:gmatch(".") do
+    >        if c == '\r' then break end  -- DOS line ending
+    >        if c == '.' then
+    >          grid[line_index][col_index] = 0
+    >        else
+    >          grid[line_index][col_index] = 1
+    >        end
+    >        col_index = col_index+1
+    >      end
+    >      line_index = line_index+1
+    >    end
+    >  end
+    >end
+- __teliva_timestamp: original
+  update:
+    >menu = {arrow="pan"}
+    >
+    >function update(window, c)
+    >  if c == curses.KEY_LEFT then
+    >    for i=1,lines*4 do
+    >      for j=2,cols*2 do
+    >        grid[i][j-1] = grid[i][j]
+    >      end
+    >      grid[i][cols*2] = 0
+    >    end
+    >  elseif c == curses.KEY_DOWN then
+    >    for i=lines*4-1,1,-1 do
+    >      for j=1,cols*2 do
+    >        grid[i+1][j] = grid[i][j]
+    >      end
+    >    end
+    >    for j=1,cols*2 do
+    >      grid[1][j] = 0
+    >    end
+    >  elseif c == curses.KEY_UP then
+    >    for i=2,lines*4 do
+    >      for j=1,cols*2 do
+    >        grid[i-1][j] = grid[i][j]
+    >      end
+    >    end
+    >    for j=1,cols*2 do
+    >      grid[lines*4][j] = 0
+    >    end
+    >  elseif c == curses.KEY_RIGHT then
+    >    for i=1,lines*4 do
+    >      for j=cols*2-1,1,-1 do
+    >        grid[i][j+1] = grid[i][j]
+    >      end
+    >      grid[i][1] = 0
+    >    end
+    >  end
+    >end
+- __teliva_timestamp: original
+  main:
+    >function main()
+    >  curses.init_pair(255, 15, 1)  -- reserved for Teliva error messages
+    >  curses.init_pair(1, 22, 189)
+    >
+    >  -- initialize grid based on commandline args
+    >  if (#arg == 0) then
+    >    -- by default, start from a deterministically random state
+    >    for i=1,lines*4 do
+    >      for j=1,cols*2 do
+    >        grid[i][j] = math.random(0, 1)
+    >      end
+    >    end
+    >  elseif arg[1] == "random" then
+    >    -- start from a non-deterministically random start state
+    >    math.randomseed(os.time())
+    >    for i=1,lines*4 do
+    >      for j=1,cols*2 do
+    >        grid[i][j] = math.random(0, 1)
+    >      end
+    >    end
+    >  -- shortcuts for some common patterns
+    >  elseif arg[1] == "pentomino" then
+    >    -- https://www.conwaylife.com/wiki/Pentomino
+    >    grid[83][172] = 1
+    >    grid[83][173] = 1
+    >    grid[84][173] = 1
+    >    grid[84][174] = 1
+    >    grid[85][173] = 1
+    >  elseif arg[1] == "glider" then
+    >    -- https://www.conwaylife.com/wiki/Glider
+    >    grid[5][4] = 1
+    >    grid[6][5] = 1
+    >    grid[7][3] = 1
+    >    grid[7][4] = 1
+    >    grid[7][5] = 1
+    >  elseif arg[1] == "blinker" then
+    >    -- https://www.conwaylife.com/wiki/Blinker
+    >    grid[7][3] = 1
+    >    grid[7][4] = 1
+    >    grid[7][5] = 1
+    >  elseif arg[1] == "block" then
+    >    -- https://www.conwaylife.com/wiki/Block
+    >    grid[5][4] = 1
+    >    grid[5][5] = 1
+    >    grid[6][4] = 1
+    >    grid[6][5] = 1
+    >  elseif arg[1] == "loaf" then
+    >    -- https://www.conwaylife.com/wiki/Loaf
+    >    grid[5][4] = 1
+    >    grid[5][5] = 1
+    >    grid[6][6] = 1
+    >    grid[7][6] = 1
+    >    grid[8][5] = 1
+    >    grid[7][4] = 1
+    >    grid[6][3] = 1
+    >  elseif file_exists(arg[1]) then
+    >    -- Load a file in the standard "plaintext" format: https://www.conwaylife.com/wiki/Plaintext
+    >    --
+    >    -- Each pattern page at https://www.conwaylife.com/wiki provides its
+    >    -- plaintext representation in a block called "Pattern Files" on the right.
+    >    --
+    >    -- For example, check out the list of Important Patterns at
+    >    -- https://www.conwaylife.com/wiki/Category:Patterns_with_Catagolue_frequency_class_0
+    >    load_file(window, arg[1])
+    >  end
+    >
+    >  -- main loop
+    >  while true do
+    >    render(window)
+    >    c = curses.getch()
+    >    update(window, c)
+    >    step()
+    >  end
+    >end