On Jun 21, 4:15 pm, Alexander Solla <alex.so...@gmail.com> wrote: > The problem is that a sum type must "name" the different types, or else it > can't give access to them. How is a function supposed to know if a value > > blah :: A :+: B > > is an A or a B? It seems possible that it could figure it out, but that > problem is undecidable in general.
Why can't you use pattern matching? We'd probably want to change the syntax a little, to tell Haskell that we want to use an anonymous sum. Something like: foo :: Bar :+: Baz -> Quux foo <Bar bar> = ... foo <Baz baz> = ... Would finding the type signature of foo be undecidable? _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
