On Sep 19, 2006, at 8:52 AM, Conor McBride wrote:
Hi folks
[EMAIL PROTECTED] wrote:
Btw, why are there no irrefutable patterns for GADTs? I mean, such
a sin
should be shame for a non-strict language...
Just imagine
> data Eq a b where Refl :: Eq a a
> coerce :: Eq a b -> a -> b
> coerce ~Refl a = b
I think you mean:
> coerce ~Refl x = x
coerce undefined True :: String
Bang you're dead. Or rather... Twiddle you're dead.
Moral: in a non-total language, if you're using indexing to act as
evidence for something, you need to be strict about checking the
evidence before you act on it, or you will be vulnerable to the
blandishments of the most appalling liars.
As Randy Pollack used to say to us when we were children, the best
thing about working in a strongly normalizing language is not
having to normalize things.
All the best
Conor
Rob Dockins
Speak softly and drive a Sherman tank.
Laugh hard; it's a long way to the bank.
-- TMBG
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