[racket-dev] [racket] Implementing contracts for async channels

Ah: one other note. When you do something like this:

((contract (-> (list/c (box/c integer?)) any)
           (λ (x) (unbox (car x)))
           'pos 'neg)
 (list (box "not an integer")))

you get an error message that has this text in the middle:

  in: the content of
      the 1st element of
      the 1st argument of
      (-> (list/c (box/c integer?)) any)

This path information is collected in the blame records.

So, instead of passing along just the blame record you got, call
"blame-add-context" so you get some stuff in that portion of the error
message.

Maybe "a value passed on" or something like that would be a good
phrase? I usually look at a few examples to pick something.

Otherwise, this looks good to merge to me (but I don't use the
generics as much as I should so if you wanted to you could try asking
for someone specifically knowledgeable to look there).

If you don't, I can push the commit to the appropriate repo. Let me know.

Robby



On Mon, Jan 19, 2015 at 5:44 PM, Alexis King <lexi.lambda at gmail.com> wrote:
> Yes, there are tests, and you can see them here.
>
> On Jan 19, 2015, at 13:29, Robby Findler <robby at eecs.northwestern.edu>
> wrote:
>
> This seemed okay, but just a quick read of the code. But did I miss
> the test cases? (I just followed the link upthread -- sorry if I need
> to look somewhere else too.)
>
> Robby
>
>
> On Mon, Jan 19, 2015 at 3:15 PM, Alexis King <lexi.lambda at gmail.com> wrote:
>
> Any update on this? If there’s anything that still needs to be changed, let
> me know—otherwise, I’ll patiently wait for the process to run its course.
> Just checking in.
>
> On Jan 16, 2015, at 10:15, Alexis King <lexi.lambda at gmail.com> wrote:
>
> Ah, that makes sense, fixed.
>
> On Jan 16, 2015, at 05:37, Robby Findler <robby at eecs.northwestern.edu>
> wrote:
>
> One comment. The contract combinators are curried so that you can do
> work on the partial applications. So don't write this:
>
> (define ((((ho-val-first-projection
> impersonate/chaperone-async-channel) ctc) blame) val)
>
> instead try to do some work earlier, when you first can. (The most
> important thing is to minimize the work done after you get the 'val'
> argument.)
>
> Robby
>
>
>
>
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