patch applied (bytestring): instance IsString for strict and lazy bytestrings. Use -XOverloadedStrings

[Don Stewart]

igloo:
> 
> Hi Don,
> 
> On Fri, Jan 04, 2008 at 09:21:15PM -0800, Donald Bruce Stewart wrote:
> > Fri Jan  4 20:59:50 PST 2008  Don Stewart <dons at galois.com>
> >   * instance IsString for strict and lazy bytestrings. Use -XOverloadedStrings
> 
> This has lots of things like:
> 
> +#if __GLASGOW_HASKELL__ >= 608
> +import Data.String
> +#endif
> 
> but Data.String and the IsString class are portable. I think you should
> use something like:

Portable, but not much use without -XOverloadedStrings ?

> #if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 608
> #define HAVE_DATA_STRING 1
> #endif
> ...similar things for hugs etc
> 
> and then test HAVE_DATA_STRING instead.
> 
> (we could test for the presence of IsString using autoconf, but
> * that's harder to write
> * it's harder to notice when the test is redundant
> * the version of base is tied to the compiler version anyway)
> 
> Thanks
> Ian

Ok, thanks. I'll have a look.