On Tue, Jun 21, 2011 at 12:53 PM, Elliot Stern <eliyahu.ben.mi...@gmail.com>wrote:
> A tuple is basically an anonymous product type. It's convenient to not > have to spend the time making a named product type, because product types > are so obviously useful. > > Tuples are not so anonymous. Although syntactic sugar complicates the issue, there is basically a data constructor named (,). > Is there any reason why Haskell doesn't have anonymous sum types? If there > isn't some theoretical problem, is there any practical reason why they > haven't been implemented? 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.
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