[Haskell-cafe] Re: Comparing GADTs for Eq and Ord

Ryan Ingram wrote:

There are many papers that talk about using GADTs to reify types in this fashion to allow safe typecasting. They generally all rely on the "base" GADT, "TEq"; every other GADT can be defined in terms of TEq and existential types.

Ah, yes. See my paper "Witnesses and Open Witnesses" http://semantic.org/stuff/Open-Witnesses.pdf -- Ashley Yakeley