On Tue, Jun 21, 2011 at 12:53 PM, Elliot Stern
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.