Richard O'Keefe wrote: > The thing is that it really seems bizarre to see this one feature > singled out for non-implementation. > > If I can do the equivalent of n+k patterns by programming in the > *type system*, why *not* in a pattern?
Do you mean by something like the following? data Z = Z data S n = S n type Plus2 a = S (S a) minus2 :: Plus2 a -> a minus2 _ = undefined -- or actually use the values, or whatever If so, I'd say that n+k patterns go well beyond this kind of "pattern aliases", particularly since they operate on arbitrary Nums, not just an inductively defined natural number type. Cheers, 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
