From: ross Date: Fri, 10 Sep 2004 22:43:20 +0000 (+0000) Subject: [project @ 2004-09-10 22:43:20 by ross] X-Git-Tag: nhc98-1-18-release~250 X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;h=7521d4f8ed4f0d2b80caa657890914df88b44fca;p=ghc-base.git [project @ 2004-09-10 22:43:20 by ross] doc tweaks --- diff --git a/Control/Monad/Fix.hs b/Control/Monad/Fix.hs index b66a6ce..c2b1669 100644 --- a/Control/Monad/Fix.hs +++ b/Control/Monad/Fix.hs @@ -10,8 +10,8 @@ -- -- Monadic fixpoints. -- --- For more details, see Levent Erkok's thesis, --- /Value Recursion in Monadic Computations/, 2002. +-- For a detailed discussion, see Levent Erkok's thesis, +-- /Value Recursion in Monadic Computations/, Oregon Graduate Institute, 2002. -- ----------------------------------------------------------------------------- @@ -25,31 +25,32 @@ module Control.Monad.Fix ( import Prelude import System.IO --- | @'fix' f@ is the least fixed point of the function @f@. +-- | @'fix' f@ is the least fixed point of the function @f@, +-- i.e. the least defined @x@ such that @f x = x@. fix :: (a -> a) -> a fix f = let x = f x in x --- | Monads having fixed points with a \`knot-tying\' semantics. --- Instances of 'MonadFix' should satisfy the laws +-- | Monads having fixed points with a \'knot-tying\' semantics. +-- Instances of 'MonadFix' should satisfy the following laws: -- --- [purity] +-- [/purity/] -- @'mfix' ('return' . h) = 'return' ('fix' h)@ -- --- [left shrinking (or tightening)] --- @'mfix' (\x -> a >>= \y -> f x y) = \y -> 'mfix' (\x -> f x y)@ +-- [/left shrinking/ (or /tightening/)] +-- @'mfix' (\\x -> a >>= \\y -> f x y) = \\y -> 'mfix' (\\x -> f x y)@ -- --- [sliding] +-- [/sliding/] -- @'mfix' ('Control.Monad.liftM' h . f) = 'Control.Monad.liftM' h ('mfix' (f . h))@, -- for strict @h@. -- --- [nesting] --- @'mfix' (\x -> 'mfix' (\y -> f x y)) = 'mfix' (\x -> f x x)@ +-- [/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. class (Monad m) => MonadFix m where -- | The fixed point of a monadic computation. - -- @'mfix' f@ executes the action 'f' only once, with the eventual + -- @'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. mfix :: (a -> m a) -> m a