Is there a general function to count list elements. I'm trying this count :: a -> [a] -> Int count x ys = length (filter (== x) ys) with this error upon loading ============= [michael@localhost ~]$ ghci count GHCi, version 6.10.1: http://www.haskell.org/ghc/  :? for help Loading package ghc-prim ... linking ... done. Loading package integer ... linking ... done. Loading package base ... linking ... done. [1 of 1] Compiling Main             ( count.hs, interpreted ) count.hs:2:29:     Could not deduce (Eq a) from the context ()       arising from a use of `==' at count.hs:2:29-32     Possible fix:       add (Eq a) to the context of the type signature for `count'     In the first argument of `filter', namely `(== x)'     In the first argument of `length', namely `(filter (== x) ys)'     In the expression: length (filter (== x) ys) Failed, modules loaded: none. Prelude> ============= Not sure what it's trying to tell me other than I need an (Eq a) somewhere. Michael