That's not enough of the program for me to figure out exactly what is going on. One possibility is that there's a struct embedded in the scribble zo that is incompatible, although I doubt that since I'm pretty sure only prefabs can be in zos.
Jay On Sat, Nov 6, 2010 at 2:03 PM, Carlos Scheidegger <carlos.scheideg...@gmail.com> wrote: > Hi Jay, > > thank you for your quick response. As you suggested, adding > '#:servlet-namespace (list "posts.rkt")' makes the problem go away - > thank you! > > What I still don't understand, though, is how posts.rkt is loading > twice, since all calls to posts.rkt come from the servlet. The full > code is this: > > (define (render-main-page request) > `(html (head (title "title")) > (body ,@(map part->xexpr (load-posts "posts"))))) > > (define (start request) > (render-main-page request)) > > load-posts is defined in posts.rkt: > > (define (load-posts path) > (define post-list (current-post-list path)) > (parameterize ([current-load-relative-directory (normalize-path path)]) > (map (lambda (post-entry) > (list post-entry > (dynamic-require (post-entry-file post-entry) 'doc))) > post-list))) > > It would make sense, in my mind, for the code to generate an error if > serve.rkt had a static define which loaded the posts. But the call to > load-posts is inside (render-main-page), which makes the error a bit > more mysterious. Also, I see this issue on v5.0.1, but offby1 on > #racket could not reproduce this on v5.0.1.900. > > This is not too important to me since my code now works, but it seems > to signal a change in behavior between these two versions. I'm posting > it here in case it turns out to be important. > > Thanks again, > -carlos > > On Sat, Nov 6, 2010 at 2:57 PM, Jay McCarthy <jay.mccar...@gmail.com> wrote: >> On Sat, Nov 6, 2010 at 12:06 PM, Carlos Scheidegger >> <carlos.scheideg...@gmail.com> wrote: >>> Hi, >>> >>> This must be a simple question, but I'm having some trouble convincing >>> Racket that one of my procedure calls respects the required contract, >>> and I'm not quite sure how to solve it. I only experience the problem >>> when running the code with serve/servlet, so I have a hunch that some >>> interaction with dynamic loading might be to blame here. >>> >>> Specifically, there's a part? procedure (from scribble/core) which >>> returns true when I run the code from the interactive racket prompt, >>> but returns false when I run the same code via a procedure passed to >>> serve/servlet. I end up getting a servlet error claiming I "broke the >>> contract (-> part? (or/c #f content?)) on part-title-content; expected >>> <part?>, given: #<part>". >>> >>> The full servlet trace is here: >>> >>> Exception >>> >>> The application raised an exception with the message: >>> >>> <collects>/scribble/core.rkt: >>> (file >>> /home/cscheid/code/racket/cscheid.net/src/generate-xexpr.rkt) >>> broke the contract (-> part? (or/c #f content?)) on >>> part-title-content; expected <part?>, given: #<part> >>> >>> Stack trace: >>> >>> raise-blame-error at: >>> line 54, column 0, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/racket/contract/private/blame.rkt >>> <unknown procedure> at: >>> line 1445, column 3, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/racket/contract/private/arrow.rkt >>> part->xexpr at: >>> line 82, column 0, in file >>> /home/cscheid/code/racket/cscheid.net/src/generate-xexpr.rkt >>> map at: >>> line 18, column 11, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/racket/private/map.rkt >>> render-main-page at: >>> line 8, column 0, in file >>> /home/cscheid/code/racket/cscheid.net/src/serve.rkt >>> <unknown procedure> at: >>> line 1445, column 3, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/racket/contract/private/arrow.rkt >>> <unknown procedure> at: >>> line 1445, column 3, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/racket/contract/private/arrow.rkt >>> <unknown procedure> at: >>> line 1445, column 3, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/racket/contract/private/arrow.rkt >>> <unknown procedure> at: >>> line 1445, column 3, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/racket/contract/private/arrow.rkt >>> <unknown procedure> at: >>> line 1445, column 3, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/racket/contract/private/arrow.rkt >>> <unknown procedure> at: >>> line 57, column 2, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/web-server/dispatchers/dispatch-servlets.rkt >>> <unknown procedure> at: >>> line 1445, column 3, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/racket/contract/private/arrow.rkt >>> <unknown procedure> at: >>> line 1445, column 3, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/racket/contract/private/arrow.rkt >>> <unknown procedure> at: >>> line 1445, column 3, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/racket/contract/private/arrow.rkt >>> <unknown procedure> at: >>> line 1445, column 3, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/racket/contract/private/arrow.rkt >>> <unknown procedure> at: >>> line 1445, column 3, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/racket/contract/private/arrow.rkt >>> select-handler/no-breaks at: >>> line 173, column 2, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/racket/private/more-scheme.rkt >>> <unknown procedure> at: >>> line 1445, column 3, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/racket/contract/private/arrow.rkt >>> <unknown procedure> at: >>> line 1445, column 3, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/racket/contract/private/arrow.rkt >>> <unknown procedure> at: >>> line 1445, column 3, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/racket/contract/private/arrow.rkt >>> <unknown procedure> at: >>> line 1445, column 3, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/racket/contract/private/arrow.rkt >>> connection-loop at: >>> line 62, column 2, in file >>> /home/cscheid/code/racket/plt-5.0.1/collects/web-server/private/dispatch-server-unit.rkt >>> >>> I'm sure I'm doing some things which are not exactly kosher - I'm >>> dynamically loading Scribble files and converting them to xexprs. My >>> wild guess is that scribble/core is somehow loading twice, and that >>> the contract is checking a structure built with one of the >>> instantiations against the predicate of the other instantiation. That >>> the setup works in an interactive Racket prompt gives me hope for a >>> solution. It's been about 6 years since I've done anything with >>> Racket, so there's a good chance I'm being terribly dense. >> >> That's exactly what the problem is. This is what the >> #:make-servlet-namespace and #:servlet-namespace keyword arguments to >> the servlet dispatching functions are all about. Each servlet normally >> gets its own new namespace, but you can specifically share modules >> among servlets (and the server). >> >> Jay >> >>> >>> Is there a simpler way to achieve what I'm going for? That is, I have >>> a list of scribble files, all in the same directory, and I want to >>> load each of them. Right now, I'm doing this roughly via: >>> >>> ; path denotes the path to the list of files, >>> ; scribble-file-list holds a list of filenames which I want to load >>> (parameterize ([current-load-relative-directory (normalize-path path)]) >>> (map (lambda (filename) (dynamic-require filename 'doc)) >>> scribble-file-list)) >>> >>> Thank you very much in advance, >>> -carlos >>> _________________________________________________ >>> For list-related administrative tasks: >>> http://lists.racket-lang.org/listinfo/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 >> > -- 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 _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
