n+k patterns

[Simon Peyton-Jones]

OK, OK, I give in! =20

Integral it remains.  I repent.

Simon

| -----Original Message-----
| From: Rijk J. C. van Haaften [mailto:rjchaaft@cs.uu.nl]=20
| Sent: 30 January 2002 17:00
| To: Simon Peyton-Jones
| Cc: haskell@haskell.org
| Subject: RE: n+k patterns
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| At 03:27 30-01-02 -0800, Simon Peyton-Jones wrote:
| >| hbc is on the Integral side, if that counts. :-)
| >| Just because ghc doesn't follow the spec isn't a good reason to=20
| >| change the spec. :-)
| >
| >I absolutely didn't say that!  All I'm saying is
| >
| >* Two of the four impls have to change regardless
| >* The change is non-de-stabilising on the rest of the report
| >* So we should think what the "best" answer is
| >
| >I argued that (Num a, Ord a) makes most sense to me.
| >You argued that (Integral a) was a conscious choice=20
| (something I don't=20
| >remember but I'm sure you're right), and is the right one anyway.
| >
| >I'd be interested to know what others think.  If there's any doubt,=20
| >we'll stay with Integral.
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| Personally I vote for keeping Integral. The strongest reason=20
| for my choice is that if we want to be sure the pattern is=20
| really correct, we need a bijection. For Integral, we have +=20
| and - to form one, but we can't construct one for Float and=20
| Double, though by this change they would be allowed in the pattern.
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| Rijk-Jan van Haaften
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