[theoh]

I'm not sure what "Hindley-Milner type signatures" means. Obviously it is intended to refer to Haskell-style type signatures. Hindley-Milner, though, usually refers to a system of type inference which is independent of syntax.

As I understand it, the author is using Hindley-Milner as if was the name of a syntax, like Backus-Naur form. But this is something I've never heard, and I wonder if the credit for the Haskell type signature style belongs just as much to Rod Burstall or David Turner, in other words I'm inclined to believe that it is something conventional that evolved over years.