gameoflife.nim

import os, strutils, terminal, random

const
  w = 60
  h = 30

# Initialize
var univ, utmp = newSeq[seq[bool]](h)
for y in 0..<h:
  univ[y].newSeq w
  utmp[y].newSeq w

univ[15][28] = true
univ[16][29] = true
univ[17][27] = true
univ[17][28] = true
univ[17][29] = true

while true:
  # Show
  stdout.eraseScreen()
  for y in 0..<h:
    for x in 0..<w:
      setCursorPos(stdout, x, y)
      if univ[y][x]:
        stdout.write "●"
      else:
        stdout.write " "
  stdout.flushFile

  # Evolve
  for y in 0..<h:
    for x in 0..<w:
      var n = 0
      for y1 in y-1..y+1:
        for x1 in x-1..x+1:
          if univ[(y1+h) mod h][(x1 + w) mod w]:
            inc n

      if univ[y][x]: dec n
      utmp[y][x] = n == 3 or (n == 2 and univ[y][x])
  swap(univ,utmp)

  sleep 200