[Haskell-cafe] ANNOUNCE: haskell-src-exts 0.4.8

Niklas Broberg niklas.broberg at gmail.com
Thu Jan 8 19:51:20 EST 2009

Fellow Haskelleers,

it is my pleasure to announce the new release of the haskell-src-exts
package, version 0.4.8:

darcs get http://code.haskell.org/HSP/haskell-src-exts

This is a bug-fix release in the wake of the flurry of bug reports I
received due to Neil Mitchell's release of hlint. Not all bugs have
been squashed, but all the ones that I could handle with fairly small
changes to the library should be. Those include deriving for MPTCs,
importing constructor symbols, inline pragmas in instance
declarations, scoped type variables, and a few more. There are some
minor non-backwards compatible changes to the abstract syntax, but
nothing too serious. The most pervasive is that the Match and PatBind
constructors have an extra argument of type Maybe Type, representing
an optional type signature. Derivings also are no longer just a list
of class names, since those classes can now have extra parameters.

Four things remain on the bug list:
- Support for explicitly kinded arguments to type families. Shouldn't
be too hard, but will require changes to the AST that I will leave for
the next release.
- Support for (un-parenthesised) higher-ranked types as arguments.
haskell-src-exts supports e.g. foo :: b -> (forall a . [a]) -> b
but not foo :: b -> forall a . [a] -> b. Supporting the latter is
simply a parser issue, but a rather tricky one.
- Correct handling of hyphened vars (an artifact of HSX/HSP) vs minus
operators. This one is nasty.
- Support for Unicode symbols for e.g. ->. Fixing that would require
me to have a Unicode-compliant editor, which it appears I don't. And I
couldn't have someone else submit a patch either, since then I
couldn't open the file anymore in my editor. So unless someone can
point out a good Unicode-aware editor for Windows, I'm afraid this is
a feature that won't be implemented.

If you find anything else that haskell-src-exts fails on, please report it.

Cheers and Happy Haskelling,


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