Hi,
Looking at the ICFP'10 paper on logical types, I tried the following:
(: carnum? ((Pairof Any Any) -> Boolean : (Pairof Number Any)))
(define (carnum? p)
(number? (car p)))
Type Checker: Expected result
with filter (((Pairof Complex Any) @ p) | (! (Pairof Complex Any) @ p)),
got filter ((Complex @ (car) p) | (! Complex @ (car) p))
in: (number? (car p))
To me, the filters seem to match, though. Any idea what is wrong here?
I want to be able to use carnum? to discriminate <Number,Any> as in:
(: test ((Pairof Any Any) -> Number))
(define (test x)
(if (carnum? x) (car x)
10))
Thanks!
-- Éric
PS: I'm using version 5.2.0.1--2011-10-26
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