11 Feb
2008
11 Feb
'08
4:34 p.m.
On Mon, Feb 11, 2008 at 01:59:09PM +0000, Neil Mitchell wrote:
Hi
(x >>= f) >>= g == x >>= (\v -> f v >>= g)
Or stated another way:
(x >>= f) >>= g == x >>= (f >>= g)
Which is totally wrong, woops.
See this page for lots of details about the Monad Laws and quite a nice explanation of where you use them: http://www.haskell.org/haskellwiki/Monad_Laws
My favorite presentation of the monad laws is associativity of Kliesli composition: (a1 >=> a2) x = a1 x >>= a2 -- predefined in 6.8 control.monad -- The laws return >=> a = a a >=> return = a a >=> (b >=> c) = (a >=> b) >=> c Stefan