[Haskell] [Haskell-cafe] Help with polymorphic functions
Wei Yuan Cai
weiyuan.cai at gmail.com
Thu May 8 15:10:08 EDT 2008
Hello,
I'm having some trouble with a polymorphic function using another
polymorphic function within. A simplified code of what I'm trying to do is
as follows:
main = print $ test 1 8
test :: a -> Int -> a
test x n = shift x n
I get the following compilation error:
Could not deduce (Data.Bits.Bits a) from the context ()
arising from a use of `shift' at test.hs:8:11-19
Possible fix:
add (Data.Bits.Bits a) to the context of
the type signature for `test'
In the expression: shift x n
In the definition of `test': test x n = shift x n
shift is defined as "a -> Int -> a"
What am I doing wrong here?
Thanks,
Weiyuan
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