Suggestion regarding (.) and map
g9ks157k at acme.softbase.org
Thu Apr 24 16:15:45 EDT 2008
Am Mittwoch, 23. April 2008 23:55 schrieb Cale Gibbard:
> Rename fmap to map
This would be really great! There is no point in having a map just for lists
and a general map for functors since the list map is the same as the list
instance’s functor map. And identifiers with a single lowercase letter in
front or after a lowercase word (fmap, foldr, etc.) are not nice, in my
> (like it was in Haskell 1.4),
It really was this way in Haskell 1.4? Why was it changed?
> and define (.) as a synonym for it.
I don’t think that this is reasonable. (.) corresponds to the little circle
in math which is a composition. So (.) = (<<<) would be far better.
> Additionally, add the instance:
> instance Functor ((->) e) where
> map f g x = f (g x)
> (and hopefully the corresponding Monad instance as well)
And hopefully the corresponding Applicative instance as well! Applicative
functors are a very nice thing. (So a big “thank you” to Conor and Ross.)
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