RosettaCodeData/Task/Langtons-ant/Elixir/langtons-ant.ex

28 lines
962 B
Elixir

defmodule Langtons do
def ant(sizex, sizey) do
{px, py} = {div(sizex,2), div(sizey,2)} # start position
move(MapSet.new, sizex, sizey, px, py, {1,0}, 0)
end
defp move(plane, sx, sy, px, py, _, step) when px<0 or sx<px or py<0 or sy<py, do:
print(plane, sx, sy, px, py, step)
defp move(plane, sx, sy, px, py, dir, step) do
{plane2, {dx,dy}} = if {px,py} in plane,
do: {MapSet.delete(plane, {px,py}), turn_right(dir)},
else: {MapSet.put(plane, {px,py}), turn_left(dir)}
move(plane2, sx, sy, px+dx, py+dy, {dx,dy}, step+1)
end
defp turn_right({dx, dy}), do: {dy, -dx}
defp turn_left({dx, dy}), do: {-dy, dx}
defp print(plane, sx, sy, px, py, step) do
IO.puts "out of bounds after #{step} moves: (#{px}, #{py})"
Enum.each(0..sy, fn j ->
IO.puts Enum.map(0..sx, fn i -> if {i,j} in plane, do: "#", else: "." end)
end)
end
end
Langtons.ant(100, 100)