[Haskell-beginners] Working out the types

[Patrick LeBoutillier]

Hi all,

Today after reading a question on StackOverflow I found myself
"working out the types" for this expression:

map . (:)

Using a pencil and paper (and more time than I has hoped) I was able
to come to the same answer as given
by ghci:

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


Here's my question: Does ghci have a verbose mode or something where
is can show you step by step how the types
are worked out? If not is there a hackage (or any other kind of)
package that can do that?

I've seen long examples worked out by people on this list (namely
Daniel Ficher) and they are easy to follow and help me
a lot, so I was wondering if such a program existed that could do it
automatically.


Thanks,

Patrick









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Patrick LeBoutillier
Rosemère, Québec, Canada