Wumpus.Basic.Monads.TurtleClass

Turtle monad and monad transformer.

The Turtle monad embodies the LOGO style of imperative drawing - sending commands to update the a cursor.

While Wumpus generally aims for a more compositional, "coordinate-free" style of drawing, some types of diagram are more easily expressed in the LOGO style.

Note - as turtle drawing with Wumpus is a local effect, there is only one instance of TurtleM. Potentially TurtleM will be removed and the functions implemented directly.

Documentation

type Coord = (Int, Int)

class Monad m => TurtleM m where

Methods

getLoc :: m (Int, Int)

setLoc :: (Int, Int) -> m ()

getOrigin :: m (Int, Int)

setOrigin :: (Int, Int) -> m ()

Instances

Monad m => TurtleM (TurtleT u m)

setsLoc :: TurtleM m => (Coord -> (a, Coord)) -> m a

setsLoc_ :: TurtleM m => (Coord -> Coord) -> m ()

movement

resetLoc :: TurtleM m => m ()

moveLeft :: TurtleM m => m ()

moveRight :: TurtleM m => m ()

moveUp :: TurtleM m => m ()

moveDown :: TurtleM m => m ()

nextLine :: TurtleM m => m ()