24 Jan
2005
24 Jan
'05
5:16 a.m.
On 24 Jan 2005, at 09:36, Keean Schupke wrote:
Ashley Yakeley wrote:
I disagree. Clearly (putStrLn "Hello" >> mzero) is not the same as mzero.
Yes it is, side effects are quite clearly not counted. The value of (putStrLn "Hello" >> mzero") is mzero.
This makes no sense to me at all. putStrLn "Hello" has type IO (). mzero (could) have type IO (). But they certainly do not denote the same element of IO ()! Monad/MonadPlus laws surely apply to the full monadic type m a, not just the value type a? Jules