[Haskell-cafe] Existential quantification of environments.
wolfgang at jeltsch.net
Tue Nov 22 13:46:47 EST 2005
Am Dienstag, 22. November 2005 17:19 schrieben Sie:
> Wolfgang Jeltsch wrote:
> >>This seems to suggest:
> >> Add a == exists (add :: a -> a -> a)
> >Doesn't "exists" normally quantify over types and not over values?
> It is quantifying over types, it is saying there exists a type "a -> a -> a"
> that has at least one value we will call "add"...
It says that there exists a value add. With quantifying over types I meant
something like this:
exists a. <some type using the type variable a>
This is how forall in GHC and Hugs looks like.
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