[Haskell-cafe] ANN: New release of regex packages

[Ross Paterson]

On Mon, Mar 05, 2007 at 03:51:47PM +0000, Chris Kuklewicz wrote:
> I would like to announce new versions of the regex-* packages.
> [...]
> Porting the backends to other Haskell compilers should
> be possible, though they may not support the polymorphic type class
> API that regex-base provides.

Some of the instances in regex-base rely on late overlapping resolution,
which is a GHC-only feature.  That is, instances overlap, with neither
subsuming the other, but they're only used outside of the overlap.

The overlap occurs in the following groups of instances:

	instance (RegexLike a b) => RegexContext a b (Array Int b)
	instance (RegexLike a b) => RegexContext a b MatchArray

	instance (RegexLike a b) => RegexContext a b [Array Int b]
	instance (RegexLike a b) => RegexContext a b [MatchArray]

	instance (RegexLike a b) => RegexContext a b [b]
	instance (RegexLike a b) => RegexContext a b [MatchArray]
	instance (RegexLike a b) => RegexContext a b [(MatchOffset,MatchLength)]

(MatchArray is a synonym for Array Int (MatchOffset, MatchLength))

Apart from that, this package (and thus the others, with a few #ifdef's)
would work with Hugs.  How about eliminating the above overlaps?