String != [Char]

[Simon Marlow]

> On Mon, Mar 19, 2012 at 9:02 AM, Christian Siefkes <christian at siefkes.net>
> wrote:
> > On 03/19/2012 04:53 PM, Johan Tibell wrote:
> >> I've been thinking about this question as well. How about
> >>
> >> class IsString s where
> >>     unpackCString :: Ptr Word8 -> CSize -> s
> >
> > What's the Ptr Word8 supposed to contain? A UTF-8 encoded string?
> 
> Yes.
> 
> We could make a distinction between byte and Unicode literals and have:
> 
> class IsBytes a where
>     unpackBytes :: Ptr Word8 -> Int -> a
> 
> class IsText a where
>     unpackText :: Ptr Word8 -> Int -> a
> 
> In the latter the caller guarantees that the passed in pointer points to
> wellformed UTF-8 data.

Is there a reason not to put all these methods in the IsString class, with appropriate default definitions?  You would need a UTF-8 encoder (& decoder) of course, but it would reduce the burden on clients and improve backwards compatibility.

Cheers,
	Simon