On Fri, 9 Jan 2009, Miguel Mitrofanov wrote:
On 8 Jan 2009, at 23:59, Henning Thielemann wrote:
GHC accepts a class declaration like
class Monad (m Maybe) => C m where
...
without having any language extension switched on. But it isn't Haskell 98,
is it?
It is.
From Report:
========================
A class assertion has form qtycls tyvar, and indicates the membership of the
type tyvar in the class qtycls. A class identifier begins with an uppercase
letter. A context consists of zero or more class assertions, and has the
general form
( C1 u1, ..., Cn un )
where C1, ..., Cn are class identifiers, and each of the u1, ..., un is
either a type variable, or the application of type variable to one or more
types.
A nice. I jumped into 4.3 and found
§ § R 32 ©
¦ 6
© ¦ 32 ¢ R ¨ © ¥
7
¤ ¢ ¨ 7
5© ¥ ¦
class
=> where
¢
§ § § §
¥ ¦ ¡ 2 §
6
© R©
7
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