Henning Thielemann wrote: > On Tue, 7 Nov 2006, Simon Marlow wrote: > >> I'd support fractional and negative fixity. It's a simple change to >> make, but we also have to adopt >> >> http://hackage.haskell.org/cgi-bin/haskell-prime/trac.cgi/wiki/FixityResolution >> >> I've added the proposal to the end of that page. In fact, the page >> already mentioned that we could generalise fixity levels, but it didn't >> mention fractional or negative values being allowed. > > Maybe that page could also mention earlier proposals and the solutions > without precedence numbers. I prefer the non-numeric approach with rules > like "(<) binds more tightly than (&&)", because it says what is intended > and it allows to make things unrelated that are unrelated, e.g. infix > operators from different libraries. Consequently a precedence relation to > general infix operators like ($) and (.) had be defined in each library.
I think that computable real fixity levels are useful, too. A further step to complex numbers is not advised because those cannot be ordered. But to be serious, the non-numeric rule based approach yields lattice-valued fixity levels. If we use a CPO, we gain ultimate expressiveness by being able to express fixity levels as fixed points of continuous functionals! Regards, apfelmus _______________________________________________ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
