<div dir="ltr">So to trace calls to the interface functions of a library I am to write a gasket for the library. I may as well put a display of the args in the gasket functions as at this point it is the same amount of code as hooking the trace. Of course then I have implemented trace. <div> </div><div>So to use trace in racket all you have to do is implement trace .. really??</div></div><div class="gmail_extra"> <div class="gmail_quote">On Mon, Jan 19, 2015 at 10:06 PM, J. Ian Johnson <<a href="mailto:ianj@ccs.neu.edu" target="_blank">ianj@ccs.neu.edu</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Yes, racket 101 (305?) is that identifiers can only be set!'d in their defining module. This is to allow necessary optimizations such as inlining. If you want to trace `f` from a different module. you can `(define (g . args) (apply f args)) (trace g)`, use `g` wherever you use `f`. You won't get any calls the library makes internally, but if you're just tracing for your own code, you'll be golden. -Ian <div><div class="h5"> ----- Original Message ----- From: "Thomas Lynch" <<a href="mailto:thomas.lynch@reasoningtechnology.com">thomas.lynch@reasoningtechnology.com</a>> To: "users" <<a href="mailto:users@racket-lang.org">users@racket-lang.org</a>> Sent: Monday, January 19, 2015 8:59:55 AM Subject: [racket] trace: set!: cannot mutate module-required identifier - alright .. how do you do this? Saw this in another thread here, but the proposed solution didnt work, well at least the way I understood it. So .. In file db-lib.rkt I have a definition: (provide db-exec) (define (db-exec a) ...) Then in racket > (enter! "db-user.rkt") Where db-citation.rkt has (require "db-lib.rkt") Now at the read-eval-print prompt I try (enter! "db-citation.rkt") And when I do (trace db-exec) I get the cannot mutate error. (Surely this must be a racket 101 type problem.) So I try to include the module at the current scope.. racket@db-citation.rkt> (require "db-lib.rkt") racket@db-citation.rkt> (require racket/trace) racket@db-citation.rkt> (trace db-exec) racket@db-citation.rkt> stdin::1130: set!: cannot mutate module-required identifier in: db-exec ok, so that doesn't work, so I start over again. This time after reading the thread on this list From: Vincent St-Amour (stamourv at <a href="http://ccs.neu.edu" target="_blank">ccs.neu.edu</a> ) Date: Mon Oct 10 13:49:46 EDT 2011 which concludes by saying 'put the trace in your program that should work', so I add this to "db-citation.rkt" (require racket/trace) (trace db-exec) And then at the prompt I get the following: Welcome to Racket v5.2.1. racket@> (enter! "db-citation.rkt") db-citation.rkt:26:11: set!: cannot mutate module-required identifier in: db-exec Alright, so what is the magic incantation here that allows one to debug/trace calls in included modules? Thanks! Thomas </div></div>____________________ Racket Users list: <a href="http://lists.racket-lang.org/users" target="_blank">http://lists.racket-lang.org/users</a> </blockquote></div> </div>