However, TypeFamilies seems too be non portable as according to this http://www.haskell.org/haskellwiki/GHC/Type_families, it works only as from GHC 6.10.1.
Henning Thielemann-4 wrote: > > Miguel Mitrofanov schrieb: >> -- {-# LANGUAGE FunctionalDependencies#-} >> -- {-# LANGUAGE MultiParamTypeClasses #-} >> {-# LANGUAGE TypeFamilies #-} >> module Register where >> -- class Register a r | a -> r >> class Register a where >> type R a >> -- instance Register Int Int >> instance Register Int where >> type R Int = Int >> -- instance Register Float Float >> instance Register Float where >> type R Float = Float >> -- instance (Register a1 r1, Register a2 r2) => Register (a1, a2) (r1, >> r2) >> instance (Register a, Register b) => Register (a, b) where >> type R (a, b) = (R a, R b) >> > So type functions are undecidable by default? > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > > ----- Yves Parès Live long and prosper -- View this message in context: http://old.nabble.com/Undecidable-instances-with-functional-dependencies-tp27555079p27605436.html Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe