Does this do what you need?
(define/contract (foo bar)
(-> (or/c 1 #t "bar" (listof string?) (listof (or/c 'a 'b))) boolean?)
#t)
(foo 1)
(foo #t)
(foo "bar")
(foo '("should work"))
(foo '(a))
(foo '(b))
(foo '(b a b a a a))
(foo "should fail")
Output:
#t
#t
#t
#t
#t
#t
#t
foo: contract violation
expected: (or/c 1 #t "bar" (listof string?) (listof (or/c (quote a)
(quote b))))
given: "should fail"
in: the 1st argument of
(->
(or/c
1
#t
"bar"
(listof string?)
(listof (or/c 'a 'b)))
boolean?)
contract from: (function foo)
On Mon, Nov 28, 2016 at 11:25 AM, Alexis King <lexi.lam...@gmail.com> wrote:
> That sounds promising, yes. Not being familiar with the guts of
> parameters, is there any way to implement this as a derived concept
> using the existing support in chaperone-procedure? As far as I can
> tell, parameters do not expose the continuation marks they use, and
> they also create thread cells, which I’m not sure that
> chaperone-procedure’s existing API would support. Would this require
> modification of procedure chaperones to support parameters directly,
> or is there some way to implement it separately?
>
> > On Nov 23, 2016, at 10:51 AM, Scott Moore <sdmo...@fas.harvard.edu>
> wrote:
> >
> > Yes, we worked with Matthew to implement the necessary hooks in
> procedure chaperones (see the 'mark options that were added to the return
> value of wrapper-proc). For the contracts we were writing, we ended up
> using these continuation marks directly.
> >
> > To implement what you're looking for, a little extra work is required to
> link up the implementation of parameters with this mechanism to get at the
> appropriate continuation marks. One question there will be whether to
> integrate it with either the existing
> > arrow contracts (carefully protecting access to the internals of the
> parameter implementation), or to just provide a standalone combinator. I
> would need to refresh my memory to see what exactly would need to be done
> for either.
> >
> > Cheers,
> > Scott
>
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