[Haskell-cafe] Re: Syntax question: class (Monad m) => MonadReader r m | m -> r where

[Mauricio]

>>> It's called a "functional dependency". This is not part of the
>>> Haskell-98 language standard; check the GHC manual.
> 
>> The documentation says "There should be more documentation, but there 
>> isn't (yet). Yell if you need it." :)
> 
> you probably don't found it. since 6.6 (or 6.8?) ghc includes great
> tutorial on fundeps derived from hugs docs
> 
> 

It's here, on 'latest' directory:

http://www.haskell.org/ghc/docs/latest/html/users_guide/type-class-extensions.html#functional-dependencies

But yes, you're right, there's a lot of good examples and
explanations. But that comment is still there, just in
the end of the first paragraph.

Best,
Maurício