[Haskell] View patterns in GHC: Request for feedback

ajb at spamcop.net ajb at spamcop.net
Mon Jul 23 21:48:58 EDT 2007

G'day all.

On Mon, Jul 23, 2007 at 05:09:01AM -0400, Dan Licata wrote:

> Simon PJ and I are implementing view patterns, a way of pattern matching
> against abstract datatypes, in GHC.  Our design is described here:
> http://hackage.haskell.org/trac/ghc/wiki/ViewPatterns

I have to agree.  Great work here, though I'm extremely dubious about
the utility of the "Maybe" patterns.

One important issue.

    "We should be able to give clear rules for when the avoidance
    of repeat computation is guaranteed."

This, for me, is a show stopper.  I really want to see these "clear rules".

Andrew Bromage

More information about the Haskell mailing list