On Wed, Jan 14, 2009 at 3:59 PM, Manlio Perillo
2) In Python it is possible to import modules inside a function.
In Haskell something like:
joinPath' root name = joinPath [root, name] importing System.FilePath (joinPath)
I just like to point out the dependently typed, Haskell-like, programming language Agda[1] which has a very nice module system with the following features: * Modules can contain other modules * Modules can be locally opened. For example: mapMaybe f m = let open Maybe in maybe nothing (just . f) m * Renaming of important names: For example: open Maybe renaming (Maybe to option; nothing to none; just to some) * Parameterized modules: For example: module Sort (A : Set) (_<_ : A -> A -> Bool) where insert : A -> List A -> List A insert y [] = y :: [] insert y (x :: xs) with x < y ... | true = x :: insert y xs ... | false = y :: x :: xs See section 2.7 of the following Agda tutorial (an open minded Haskell hacker should be able to read that section on its own): http://www.cs.chalmers.se/~ulfn/darcs/AFP08/LectureNotes/AgdaIntro.pdf Hopefully Haskell can borrow some of these ideas sometime. regards, Bas [1] http://wiki.portal.chalmers.se/agda/