Re: [Haskell-cafe] Type families are awesome

27 Jan 2009

      Thanks Luke,

Works great.

On Wed, Jan 21, 2009 at 7:35 PM, Luke Palmer  wrote:
...
2009/1/21 John Ky 
...
*Main> let x = lookup
*Main> let y = Fx.Data.Map.lookup
<interactive>:1:8:
    Ambiguous type variable `ma' in the constraint:
      `Fx.Data.Map.MapType ma'
        arising from a use of `Fx.Data.Map.lookup' at <interactive>:1:8-25
    Probable fix: add a type signature that fixes these type variable(s)
I think this is just the monomorphism restriction. Turn it off with
-XNoMonomorphismRestriction, or add a parameter to the binding:
let x k = lookup k
Luke