Syntax extensions (was: RE: The Future of Haskell discussion at the Haskell Workshop)

Malcolm Wallace Malcolm.Wallace@cs.york.ac.uk
Wed, 10 Sep 2003 13:56:13 +0100


"Simon Marlow" <simonmar@microsoft.com> writes:

> Of course, if we change the language that is implied by -fglasgow-exts now,
> we risk breaking old code :-)  Would folk prefer existing syntax extensions
> be moved into their own flags, or left in -fglasgow-exts for now?  I'm
> thinking of:
> 
>   - implicit parameters
>   - template haskell
>   - FFI
>   - rank-N polymorphism (forall keyword)
>   - recursive 'do' (mdo keyword)

The obvious approach is to do both (in exactly the manner of
{-fffi, -farrows, -fwith}), namely to introduce a separate flag
for each extension, but (temporarily) retain -fglasgow-exts as
a catch-all for the complete set.  Eventually, -fglasgow-exts
could disappear.

With this suggestion, I would certainly be in favour of separate
flags for existing extensions.

Regards,
    Malcolm