26 Jan
2005
26 Jan
'05
1:37 p.m.
Hello,
On Tue, 25 Jan 2005 22:49:06 -0500, Paul Hudak
Good point; I suppose the constraint m /= _|_ should be added to the law.
This is not enough, at least in some cases. Consider lists, and m being an infinite list, e.g. [1..] Then we need that the inifinte concatenation of a empty lists gives us the empty list which is not the case. -Iavor
ajb@spamcop.net wrote:
The problem is this "law":
m >>= \k -> mzero === mzero
I think this "law" is untrue for _all_ MonadPlus instances, and you can trivially check this by setting m to bottom.
Cbheers, Andrew Bromage
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