
my actual use case looks more like this:
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE FlexibleInstances, TypeSynonymInstances #-}
import Data.Text as T
class ShowT a where
showT :: a -> String
instance ShowT T.Text where
showT = show
instance ShowT String where
showT = show
main = print (showT "Hello!")
Ambiguous type variable `a0' in the constraints:
(ShowT a0) arising from a use of `showT' at default.hs:16:15-19
(Data.String.IsString a0) arising from the literal `"Hello!"'
So I actually want to define a default instance for a typeclass I
define that uses isString instances.
On Sat, Apr 21, 2012 at 6:24 PM, Daniel Peebles
I think it'll be hard to do that without putting Text in base, which I'm not sure anyone wants to do.
Dan
On Sat, Apr 21, 2012 at 8:20 PM, Greg Weber
wrote: I would like to default IsString to use the Text instance to avoid ambiguous type errors. I see defaulting capability is available for Num. Is there any way to do this for IsString?
Thanks, Greg Weber
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