For a detailed discussion, see Levent Erkok's thesis,
Value Recursion in Monadic Computations, Oregon Graduate Institute, 2002.
Monads having fixed points with a 'knot-tying' semantics.
Instances of MonadFix should satisfy the following laws:
mfix (return . h) = return (fix h)
- left shrinking (or tightening)
mfix (\x -> a >>= \y -> f x y) = a >>= \y -> mfix (\x -> f x y)
mfix (liftM h . f) = liftM h (mfix (f . h)),
for strict h.
mfix (\x -> mfix (\y -> f x y)) = mfix (\x -> f x x)
This class is used in the translation of the recursive do notation
supported by GHC and Hugs.
|mfix :: (a -> m a) -> m a||Source|
|The fixed point of a monadic computation.
mfix f executes the action f only once, with the eventual
output fed back as the input. Hence f should not be strict,
for then mfix f would diverge.
|fix f is the least fixed point of the function f,
i.e. the least defined x such that f x = x.
|Produced by Haddock version 0.8|