I sometimes do this
-<
class (Show c) => C c where
foo = show c
data CObj= forall c. (C c, Show c) => CObj c
instance C Cobj where -- my existantial type should also implement class C
foo (CObj c) = foo c
->
Would it be a nice idea to just write
-<
data CObj= forall c. (C c, Show c) => CObj c
deriving (C) ?
->
?
Or is this already possible?
Marc Weber
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