Types in Haskell

Posted by Linda Cohen on Stack Overflow See other posts from Stack Overflow or by Linda Cohen
Published on 2010-05-11T18:41:53Z Indexed on 2010/05/11 19:14 UTC
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haskell

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inferred-type

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type

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type-inference

I'm kind of new in Haskell and I have difficulty understanding how inferred types and such works.

map :: (a -> b) -> [a] -> [b]
(.) :: (a -> b) -> (c -> a) -> c -> b

What EXACTLY does that mean?

foldr :: (a -> b -> b) -> b -> [a] -> b
foldl :: (a -> b -> a) -> a -> [b] -> a
foldl1 :: (a -> a -> a) -> [a] -> a

What are the differences between these?

And how would I define the inferred type of something like

foldr map

THANKS!

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