On Jul30, Claus Reinke wrote: > >>one could turn that promise into a type-checked guarantee by using > >>explicit sum types (and thus structural rather than name-based typing), > >>but that gets awkward in plain haskell. > > > >I don't think the choice of whether you label your variants with names > >or with numbers (in1, in2, in3...) has anything to do with the choice of > >whether you require your cases to be exhaustive or not. > > i was talking about name-based (as in: this is the sum type named List) > vs structural (as in: this is the sum type build from Cons and Nil) typing. > the former hides (in-)exhaustiveness from the type system, the latter > exposes it. >
I don't think the juxtaposition you're setting up here, between "name-based" and "structural", is correct. You could just as well choose the elimination form for "name-based" sum types (i.e., datatypes) to be an exhaustive case analysis. It just happens that Haskell chooses to permit non-exhaustive case expressions. -Dan _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
