[Haskell-cafe] Re: Type question in instance of a class

Maurí­cio briqueabraque at yahoo.com
Tue Nov 18 03:01:06 EST 2008

>  >> (...) One way to code this would be to use functional dependencies:
>  >>
>  >> class MyClass r s | r -> s where function :: r -> s
>> One additional  problem is that I  (believe I) need that  my class takes
>> just  one type
> FDs with just one type parameter are called ATs :)
> (FDs = functional dependencies, ATs is a new feature of ghc 6.8/6.10)

Sorry for asking, but I tried to read 6.10 extension documentation
in user's guide, as well as release notes for 6.10 and 6.8, and
could not figure out what exactly are ATs. Can you give me a direction?


More information about the Haskell-Cafe mailing list