This error probably has nothing to do with the Web server. If you run #lang racket (eval '(#%top-interaction . (last (1 2 3))))
Then you get the error: . compile: unbound identifier (and no #%app syntax transformer is bound) in: #%top-interaction If you run the same expression from the REPL you get the error: . . procedure application: expected procedure, given: 1; arguments were: 2 3 'eval' rarely makes sense with one argument. Jay On Thu, Sep 30, 2010 at 2:40 AM, Steve Knight <stk...@gmail.com> wrote: > Hello, > > I'm using Racket 5.0.1 (from emacs) and I'm having trouble > understanding some behaviour I'm seeing in the web server. > > If I start a servlet and dispatch some URL to this function: > > (define (ev request) > `(div (h1 "Last = " ,(format "~A" (last '(1 2 3)))) > (h1 "Last = " ,(format "~A" > (with-handlers ((exn:fail? (lambda > (f) "FAIL"))) > (eval '(#%top-interaction . > (last (1 2 3))))))))) > > I get "Last = 3" and "Last = FAIL" as the result, and I think I > understand why. Looking at the code of the web-server I think it is > because the web-server places each servlet in its own namespace and > that namespace does not include racket/list. Therefore I think what > is happening is that the first 'last' is compiled (from #lang racket) > and so is fine and the second 'last' is not and so relies on the > current-namespace. Now because of the namespace fandangling done to > preserve servlet separation, current-namespace is made from > 'make-base-namespace' and so does not include racket/list. So far so > good. > > I can make this work by changing the call to eval to pass a well-known > namespace to 'eval' but that is a bit awkward (and feels a bit wrong). > It seems like the right thing to do is to use the > #:servlet-namespace option in serve/servlet (i.e. > "#:servlet-namespace '(racket/list)") but when I try it it has no > obvious effect although looking at the web-server code it seems like > it should. > > Can someone tell me what I'm doing wrong?! > > Steve > _________________________________________________ > For list-related administrative tasks: > http://lists.racket-lang.org/listinfo/users > -- Jay McCarthy <j...@cs.byu.edu> Assistant Professor / Brigham Young University http://teammccarthy.org/jay "The glory of God is Intelligence" - D&C 93 _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
