examples/rosettacode/one_dimensional_cellular_automata.nit

   1 #!/usr/bin/env nit
   2 #
   3 # This file is part of NIT ( http://www.nitlanguage.org ).
   4 # This program is public domain
   5
   6 # Task: One-dimensional_cellular_automata
   7 # SEE: <http://rosettacode.org/wiki/One-dimensional_cellular_automata>
   8 module one_dimensional_cellular_automata
   9
  10 fun evolve(cells: SequenceRead[Char]): SequenceRead[Char]
  11 do
  12         var res = new Array[Char]
  13         for i in [0..cells.length[ do
  14                 var n = neighboors(i, cells)
  15                 if cells[i] == '#' then
  16                         res.add(b_to_char(n == 1))
  17                 else
  18                         res.add(b_to_char(n == 2))
  19                 end
  20         end
  21         return res
  22 end
  23
  24 fun b_to_char(b: Bool): Char do if b then return '#' else return '_'
  25
  26 fun neighboors(i: Int, cells: SequenceRead[Char]): Int
  27 do
  28         var res = 0
  29         if i > 0 and cells[i-1] == '#' then res += 1
  30         if i < cells.length - 1 and cells[i+1] == '#' then res += 1
  31         return res
  32 end
  33
  34 var ary = "_###_##_#_#_#_#__#__".chars
  35 loop
  36         print ary.join
  37         var nxt = evolve(ary)
  38         if ary == nxt then break
  39         ary = nxt
  40 end