舵龟基于helm游戏引擎的Turtle模块。例子:


import FRP.Helm

import FRP.Helm.Window as Window

import FRP.Helm.Turtle



myprogram :: FieldAction

myprogram = do

    setSpeed 20

    penUp

    goto ((-200), 0)

    penDown

    koch 500



koch :: Int -> FieldAction

koch n

    | n <= 10 = fd 5

    | otherwise = do

        koch (n `div` 3)

        lt 60

        koch (n `div` 3)

        rt 120

        koch (n `div` 3)