gale at sefer.org
Wed Apr 29 04:30:27 EDT 2009
Michael Rice wrote:
> -- comb is a combinator for sequencing operations that return Maybe
> comb :: Maybe a -> (a -> Maybe b) -> Maybe b
> comb Nothing _ = Nothing
> comb (Just x) f = f x
comb is essentially the same as something in the Prelude:
it is just (>>=) specialized to Maybe.
(>>=) :: Monad m => m a -> (a -> m b) -> m b
> Now what am I misunderstanding in the code below?
> lst = [('A',65),('B',66),('C',67),('D',68)]
Brandon S. Allbery wrote:
> ...it defaulted to [(Char,Integer)]. This is a manifestation
> of the Monomorphism Restriction...
While it may be debatable whether the Monomorphism
Restriction is helpful in compiled code, it is unquestionably
a major nuisance at the GHCi prompt, for this and other
I highly recommend that you create a .ghci file in your home
directory containing the line:
In my opinion, MR should be off by default in GHCi.
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