On Tuesday 10 July 2007, Jim Apple wrote: > On 7/9/07, Jonathan Cast <[EMAIL PROTECTED]> wrote: > > GADTs don't change anything (at least, not the last time I checked). > > GHC (in HEAD, at least) eliminates this wart for any datatype declared > with GADT syntax. > > http://www.haskell.org/ghc/dist/current/docs/users_guide/data-type-extensio >ns.html#gadt-style > > "Any data type that can be declared in standard Haskell-98 syntax can > also be declared using GADT-style syntax. The choice is largely > stylistic, but GADT-style declarations differ in one important > respect: they treat class constraints on the data constructors > differently. Specifically, if the constructor is given a type-class > context, that context is made available by pattern matching."
I'll definitely check this out; I've been quite annoyed by this restriction in the past. Jonathan Cast http://sourceforge.net/projects/fid-core http://sourceforge.net/projects/fid-emacs _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
