bugs from n+k patterns (was: Re: Preventing/handling space leaks)

Derek Elkins ddarius at hotpop.com
Thu Dec 11 14:43:57 EST 2003

On Thu, 11 Dec 2003 06:23:51 -0800
"Iavor S. Diatchki" <diatchki at cse.ogi.edu> wrote:

> Henk-Jan van Tuyl wrote:
> > 2) It is likely, that n+k patterns dissapear in the next Haskell 
> > standard. If you don't like to rewrite, test and debug all your 
> > software every few years, don't use any language/compiler features 
> > that are likely to dissapear. This is another thing that might cost 
> > companies a lot of money.
> i didn't know anyone is working on a next haskell standard.  have n+k 
> patterns been made obsolete?

I don't know of any other feature that has had this, "Many people feel
that n+k patterns should not be used. These patterns may be removed or
changed in future versions of Haskell.", said about it in the (online)
Report (3.17.2).  Obviously, the second sentence is vacuous; anything
can be removed or changed in future versions of Haskell, but the intent
seems clear (and is somewhat self-fulfilling).

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