On Monday 01 November 2004 23:40, Jon Fairbairn wrote: > if Circle.destruct:: Shape -> (Double -> t) -> t -> t and > similarly Square.destruct, we'd just have to write the case > as > > Circle.destruct s f (Square.destruct s g (error "impossible")) > > ie the .destructs take a Shape, a function to apply if it > matches and a value to return if it doesn't.
Ah, I see. It's rather more ugly but it is a better match for what Haskell does at the moment, isn't it? (IIRC patterns are matched in the order they appear in the source). > Apart from matching up with the names there's not much to > choose between one destructor and many, except possibly when > one considers something like: > > case e of > Square s -> ... > _ -> ... > > particularly if the type has more than two constructors. True. Anyway, we don't really want to abandon pattern matching syntax, do we? Ben _______________________________________________ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
