On 2013-08-07 08:18:41 -0700, Eric Dobson wrote:
> Ok, now I'm not so sure it is possible. Can you give what you think
> the contracts should be for your posn example? The issue that I see is
> that the parametricity is shared across different functions and I
> don't know how that is represented with racket contracts.
The contracts should be something like
make-posn --> (-> X Y (posn X Y))
posn-x --> (-> (posn X Y) X)
posn-y --> (-> (posn X Y) Y)
where X = (new-∀/c 'X)
Y = (new-∀/c 'Y)
This is similar to how `contract-out` works with the #:exists and
#:forall keywords.
Cheers,
Asumu
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