On Tue, 2010-11-16 at 00:55 -0500, Daniel Peebles wrote: > If I were to guess, I'd say it's because there are two major "spaces" > in Haskell, the type level and the value level. They never interact > directly (their terms are never juxtaposed) so there's not much chance > for confusion. "Typeclass constructors" and type constructors do > however live in the same space. The fact that you propose "instance > String String" might be odd to some. It's still unambiguous, but isn't > necessarily the most clear: > > > (with higher-sorted kind polymorphism, MPTCs, type families, and > GADTs) > > > instance String String String String String where > data String String String String String where String :: String > String String String String > > > :-)
data Buffalo = Buffalo
class Buffalo b where
type familly Buffalo b
instance Buffalo Buffalo where
type familly Buffalo Buffalo = Buffalo
instance Buffalo b => Buffalo (Buffalo b) where
type familly Buffalo (Buffalo b) = b
But:
data Buffalo b = Buffalo b
class Buffalo b where
type familly Buffalo b
-- Is it about Buffalo (type) b being buffalo or result of
-- Buffalo (type function) being Buffalo?
instance Buffalo b => Buffalo (Buffalo b) where
type familly Buffalo (Buffalo b) = b
Regards
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