It is extremely unlikely that out of date .zo files could cause this, altho it is, in theory, possible.
Robby On Wed, Oct 23, 2013 at 7:55 PM, Erik Pearson <e...@adaptations.com> wrote: > Thanks Robby, a nice teaching gift. > > I think the problem has "gone away". Realizing my ad-hoc test was run from > the file in which url triggers the error, I set about to embed the test in > the file / dr racket window that generates url. > > I ran a test function, starting very simple and step by step getting > closer to the one which fails, but was unable to trigger the error. Finally > I returned to the original function, and now I can't trigger the error with > it either, even with all the test code removed. > > Could it have been a stuck compiled file? Overwritten finally when I was > running the tests? I see that my Dr Racket's "Populate 'compiled' > directories" is enabled. From my CL days, if I ran into something like this > I might blow away all the compiled files and recompile everything from > scratch.. Anyway it works now and I'm back to working on the real problems > ... > > Thanks again for all the lightening fast help! > > Erik. > > > On Wed, Oct 23, 2013 at 4:58 PM, Robby Findler < > ro...@eecs.northwestern.edu> wrote: > >> Since there's little background here, I thought I'd just add that this >> feature you're coming across is one of the critical things that underpins >> Racket and differentiates it from languages like python and ruby. That is, >> what you're seeing is that Racket has a way to make unforgeable values. >> This ability is (in addition to lots of stuff, notably macros) is what >> makes it possible for Racket's class system to be a library and lots of >> other things that you'd expect to be built into a language to also be >> libraries. >> >> As a little example, if you have these files: >> >> ;; a.rkt >> #lang racket >> (struct url (stuff more-stuff)) >> >> ;; b.rkt >> #lang racket >> (struct url (stuff more-stuff)) >> >> ;; c.rkt >> #lang racket >> (require (prefix-in a: "a.rkt") (prefix-in b: "b.rkt")) >> (b:url-stuff (a:url 1 2)) >> >> >> you'll see an error message very similar to the one you reported. >> >> It is the struct declaration's location (technically when it is evaluated >> -- you can even stick them inside functions and each time you call the >> function you get a different notion of "url") that determines which is >> which. >> >> This is why, for example, you cannot see the hidden stuff inside the >> class and object structs. Or, for that matter functions! The "lambda" that >> #lang racket exports is a lot fancier than the low-level built-in lambda, >> and that is all implemented with structs. Indeed, you cannot tell what is >> primitive and what is implemented with a struct in some private file >> (unless you read the source code). Or, to put it another way: everything is >> implemented with struct and the runtime system is just good at optimizing a >> small subset of the structs where performance matters. >> >> Robby >> >> >> >> On Wed, Oct 23, 2013 at 5:38 PM, Erik Pearson <e...@adaptations.com>wrote: >> >>> On Wed, Oct 23, 2013 at 3:31 PM, Jay McCarthy <jay.mccar...@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. >>>> >>> >>> Would the operative places to look be the point at which the url object >>> is created and then where it is used? In other words, if it is created in >>> the context of net/url (i.e. a module where net/url is required) and used >>> in a module with adaptnet/url required, it will look like a #<url> (when >>> printed) but not be a url? according to adaptnet/url's url-structs, and >>> where the object travels in between doesn't make a difference? >>> >>> >>>> 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 <e...@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. >>>> > >>>> > >>>> > >>>> > ____________________ >>>> > Racket Users list: >>>> > http://lists.racket-lang.org/users >>>> > >>>> >>>> >>>> >>>> -- >>>> Jay McCarthy <j...@cs.byu.edu> >>>> Assistant Professor / Brigham Young University >>>> http://faculty.cs.byu.edu/~jay >>>> >>>> "The glory of God is Intelligence" - D&C 93 >>>> >>> >>> >>> >>> -- >>> Erik Pearson >>> Adaptations >>> ;; web form and function >>> >>> ____________________ >>> Racket Users list: >>> http://lists.racket-lang.org/users >>> >>> >> > > > -- > Erik Pearson > Adaptations > ;; web form and function >
____________________ Racket Users list: http://lists.racket-lang.org/users
