[racket] struct contract violation problem

Or you defined 

(struct url ...) 

somewhere :-) 


On Oct 23, 2013, at 6:31 PM, Jay McCarthy <jay.mccarthy at gmail.com> wrote:

> Here are two ideas.
> 
> 1) You simply have an old use of the original net/url. When #<url> is
> printed, it uses the symbolic name and you can't really figure out
> what the underlying code came from. I would do a grep to make sure
> this is not the case.
> 
> 2) You are using namespaces somewhere and actually have two instances
> of the same module somewhere where a value produced by copy 1 is going
> to copy 2. This is possible with the Web server if you don't set up
> the servlet namespace properly:
> 
> http://docs.racket-lang.org/web-server-internal/dispatch-servlets.html#(part._namespace)
> 
> On Wed, Oct 23, 2013 at 4:25 PM, Erik Pearson <erik at adaptations.com> wrote:
>> Excuse my poor experience with contracts, this is probably an easy one.
>> 
>> I'm using a copy of net/url and have a strange problem. The copied library
>> is working fine in general, but this problem cropped up today:
>> 
>> struct:exn:fail:contract:blame url-port: contract violation
>> expected: url?
>> given: #<url>
>> in: the 1st argument of
>> (-> url? (or/c #f number?))
>> contract from:
>> /home/epearson/work/racket/github/adaptnet/url-structs.rkt
>> blaming: /home/epearson/work/racket/github/racqueb/httpc.rkt
>> at: /home/epearson/work/racket/github/adaptnet/url-structs.rkt:4.28
>> 
>> The error is thrown in my usage of url-port which is being passed a
>> perfectly good url struct object. The file is requiring the copied
>> url-structs. If I play with the function that is being blamed in httpc.rkt
>> via the repl in dr racket, this specific error is not thrown. The call to
>> (url-port url) succeeds without throwing this contract exception.
>> 
>> From my primitive understanding, I'm flummoxed: Why is a #<url> not a url?
>> 
>> I suspected that there may have been a leftover require of net/url confusing
>> things, but I can't find any in my code.
>> 
>> Using racket head from github 5.90.0.9--2013-10-20(d6610289/d)
>> 
>> Help!
>> 
>> Thanks,
>> Erik.
>> 
>> 
>> 
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> 
> 
> 
> -- 
> Jay McCarthy <jay at cs.byu.edu>
> Assistant Professor / Brigham Young University
> http://faculty.cs.byu.edu/~jay
> 
> "The glory of God is Intelligence" - D&C 93
> ____________________
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