On Sun, Jan 8, 2012 at 11:21 PM, wren ng thornton
Couldn't the following work?
class Functor f where type C f :: * -> Constraint type C f _ = ()
I get a parse error from that. The equivalent: class Functor f where type FC f :: * -> Constraint type FC f a = () gives the error: Number of parameters must match family declaration; expected 1 In the type synonym instance default declaration for `FC' In the class declaration for `Functor'
It seems to me that adding const to the type level (either implicitly or explicitly) is cleaner and simpler than overloading () to be Constraint, *->Constraint, *->*->Constraint,...
-- Live well, ~wren
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