Copyright | (c) Andy Gill 2001, (c) Oregon Graduate Institute of Science and Technology, 2002 |
---|---|
License | BSD-style (see the file libraries/base/LICENSE) |
Maintainer | libraries@haskell.org |
Stability | experimental |
Portability | portable |
Safe Haskell | Trustworthy |
Language | Haskell2010 |
Monadic fixpoints.
For a detailed discussion, see Levent Erkok's thesis, Value Recursion in Monadic Computations, Oregon Graduate Institute, 2002.
Documentation
class Monad m => MonadFix m where Source #
Monads having fixed points with a 'knot-tying' semantics.
Instances of MonadFix
should satisfy the following laws:
- purity
mfix
(return
. h) =return
(fix
h)- left shrinking (or tightening)
mfix
(\x -> a >>= \y -> f x y) = a >>= \y ->mfix
(\x -> f x y)- sliding
, for strictmfix
(liftM
h . f) =liftM
h (mfix
(f . h))h
.- nesting
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.
MonadFix [] # | |
MonadFix Maybe # | |
MonadFix IO # | |
MonadFix Par1 # | |
MonadFix Last # | |
MonadFix First # | |
MonadFix Product # | |
MonadFix Sum # | |
MonadFix Dual # | |
MonadFix NonEmpty # | |
MonadFix Option # | |
MonadFix Last # | |
MonadFix First # | |
MonadFix Max # | |
MonadFix Min # | |
MonadFix Identity # | |
MonadFix ((->) r) # | |
MonadFix (Either e) # | |
MonadFix f => MonadFix (Rec1 f) # | |
MonadFix (ST s) # | |
MonadFix (ST s) # | |
(MonadFix f, MonadFix g) => MonadFix ((:*:) f g) # | |
MonadFix f => MonadFix (Alt * f) # | |
MonadFix f => MonadFix (M1 i c f) # | |
(MonadFix f, MonadFix g) => MonadFix (Product * f g) # | |