Alex Ferguson wrote:
| Frank A. Christoph:
| > I hope that Either will be renamed to (+), or at
| > least deprecated in favor of (+).
|
| I'd basically agree with Frank here, though presumably for consistency
| with Koen's (very reasonable) proposals, this would need to be the
| symbol (:+:) -- or characters to that effect -- for consistency.
I agree.
Note that the symbol (+) as a type, would become a type _variable_. I
think, just as it is usefule to have (+) as a formal parameter of a
function, it is useful to have operators as type variables also.
See the following example (in an adapted Fudget library):
class Fudget (-->) where
makeFudget :: (a --> b) -> (a `F` b)
instance Fudget F where
makeFudget = id
instance Fudget SP where
makeFudget = absF
instance Fudget (->) where
makeFudget = mapF
We could even write:
type a :=> b = F a b
type a :-> b = SP a b
If class names are also subject to this convention, then we can write
things like:
class a :< b where -- subtyping
coerce :: a -> b
foo :: (a :< Int) => a -> a -> Int
foo x y = coerce x + coerce y
I like it!
Regards,
Koen.
--
Koen Claessen,
[EMAIL PROTECTED],
http://www.cs.chalmers.se/~koen,
Chalmers University of Technology.
