Re: How to user-define a type equality constraint?
Anthony Clayden <[email protected]> Tue, 6 Apr 2021 23:44:14 +1200
| Newsgroups | gmane.comp.lang.haskell.glasgow.user |
|---|---|
| Message-ID | <CAM7nRYReHaTYG9fFWh9MZD=dayaC5RGutRk_aBT8GUxH-oDpEg@mail.gmail.com> |
> But why does this matter? Because I want the semantics of that equality constraint, without switching on any of these, which I don't otherwise use: GADTs TypeFamilies TypeOperators And if that means I can't use infix `~` in my constraints, I'll put up with that. (I'd user-define a conventional class, say `TypeCast`. Could be that has to be defined in terms of `~`, in which case I'd put that in a shim module as the only place with those extensions.) _______________________________________________ Glasgow-haskell-users mailing list [email protected] http://mail.haskell.org/cgi-bin/mailman/listinfo/glasgow-haskell-users