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On Tue, 20 Sep 2005, Michael Sperber wrote:
Andre van Tonder <andre@xxxxxxxxxxxxxxxxx> writes:It seems that the constructor paradigm chosen in the draft does not easily accommodate future extensions for pattern matching. The problem is that a constructor can be many to one. E.g., in (define-type foo (x y) (fields a immutable (+ x y))) we cannot automatically generate a pattern that can be used (like in MzScheme): (match (make-foo 1 2) ((make-foo x y) .....))This is true as far as pattern matching by position is concerned. I personally think this is a good thing, as pattern matching by position scales very poorly.
I agree that it scales poorly, but the same objection arguably applies to /constructors/ (and parents) with positional arguments, yet these are built into the basic syntax.
Cheers Andre