rule110.snow

-- create a grid of size
createGrid size
  : Int -> Array<Bool>
  = if 0 < (size - 1)
    then (push (createGrid (size - 1)) false)
    else [false]

isAlive a b c
  : String -> String -> String -> Bool
  = if a and b and c        -- 111
    then false              --  0
    else if a and b and !c  -- 110
    then true               --  1
    else if a and !b and c  -- 101
    then true               --  1
    else if a and !b and !c -- 100
    then false              --  0
    else if !a and b and c  -- 011
    then true               --  1
    else if !a and b and !c -- 010
    then true               --  1
    else if !a and !b and c -- 001
    then true               --  1
    else false              -- 000
                            --  0
idxOf i len
  : Int -> Int -> Int
  = (i + len) mod len

nextCell grid x
  : Array<Bool> -> Int -> Bool
  = (λlen ->
    (λa   ->
    (λb   ->
    (λc   -> isAlive a b c)
    (nth grid (idxOf (x + 1) len)))
    (nth grid          x          ))
    (nth grid (idxOf (x - 1) len)))
    (length grid)

displayCell cell
  : Bool -> String
  = if cell then "#" else " "

nextGen grid idx
  : Array<Bool> -> Int -> Array<Bool>
  = if idx < (length grid)
    then (push nextGen (idx + 1))
    else [nextCell grid idx]

joinStr sep arr
  : String -> Array<Bool> -> String
  = if (length arr) > 0
    then (sep + (head arr)) + (joinStr sep (tail arr))
    else ""

map f arr
  - : (a -> b) -> Array<a> -> Array<b>
  = if length arr == 0
    then []
    else [f (head arr)] + map f (tail arr)


display grid
  : Array<Bool> -> IO
  = head [grid, (print (joinStr "" (map displayCell grid)) "\n")]

run count grid
  : Array<Bool> -> Array<Bool>
  = run (count + 1) (nextGen (display grid) 0)

-- main
--   : IO
--   = (\starting_grid ->
--     (\grid -> run 0 grid)
--     (display starting_grid))
--     (push  (createGrid 9) true)

main = print (map (λx -> x + 1) [1, 2, 3])