[Haskell-cafe] Can't explain this error
Dinh Tien Tuan Anh
tuananhbirm at hotmail.com
Tue Jul 12 08:39:49 EDT 2005
i have just encountered another type error.
This program tries to print out partitions of a positive integer (i guess)
parts 0 = [[]]
parts x = [concat (map (y:) parts(x-y) | y<-[1..(x `div` 2)]]
and got this error:
**** Expression : map (y:) parts(x-y)
**** Term : map
**** Type : (e->f) -> [e] -> [f]
**** Does not match : a -> b -> c -> d
why do i have this error ? How to fix it ?
Thanks a lot
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