In the original language design the Haskell committee considered allowing multiple occurrences of the same variable in a pattern (with the suggested equality tests), but it was rejected in favour of simplicity.
-- Lennart On Fri, May 15, 2009 at 11:30 AM, Sittampalam, Ganesh <ganesh.sittampa...@credit-suisse.com> wrote: > Conor McBride wrote: >> On 15 May 2009, at 09:11, Sittampalam, Ganesh wrote: >>> >>> but then pattern matching can introduce Eq constraints which some >>> might see as a bit odd. >> >> Doesn't seem that odd to me. Plenty of other language features come >> with constraints attached. > > It's the introduction of a constraint from tweaking a pattern that is > odd, I think. By way of precedent H98 rejected this kind of idea in > favour of putting 'fail' into Monad. > > Ganesh > > =============================================================================== > Please access the attached hyperlink for an important electronic > communications disclaimer: > http://www.credit-suisse.com/legal/en/disclaimer_email_ib.html > =============================================================================== > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
