+#ifndef __HUGS__
+-- | 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/]
+-- @'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)@
+--
+-- This class is used in the translation of the recursive @do@ notation
+-- supported by GHC and Hugs.