Re: Proposal: Improving the IsString String instance

25 Aug 2013

      Am 24.08.2013 19:52, schrieb Edward Kmett:
...
I would like to replace this instance with
instance a ~ Char => IsString [a] where
   fromString = id
Your complaint proves my concerns about those FlexibleInstances. The 
best instance is a Haskell 98 instance:

class IsCharList a where
    fromCharList :: [a] -> String

instance IsCharList Char where
    fromCharList = id

instance IsCharList a => IsString [a] where
    fromString = fromCharList

This is both the most flexible solution and it is portable.

http://www.haskell.org/haskellwiki/List_instance

Re: Proposal: Improving the IsString String instance

Henning Thielemann