Hi
in spite of their similarity, all of these constructs handle some of the
monadic aspects differently. the translations of pattern guards not only
embed statements in "guard", they also embed the right hand sides of
generators in "return". translations of list comprehensions only lift
statements. translation of do-notation lifts neither statements nor
generators.
does this clarify things?
No. Pattern guards are "obvious", they could only work in one
particular way, and they do work that way. They make common things
easier, and increase abstraction. If your only argument against them
requires category theory, then I'd say that's a pretty solid reason
for them going in.
The argument that people seem to be making is that they are confusing,
I completely disagree.
f value | Just match <- lookup value list = g match
Without thinking too hard, I am curious how anyone could get the
meaning of this wrong if they understand the rest of Haskell. Can you
show a concrete example, where you think a user would get confused?
Thanks
Neil
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