[Chicken-janitors] #842: trace: Procedure called with incorrect number of arguments (but still magically works)

[Chicken Trac]

#842: trace: Procedure called with incorrect number of arguments (but still
magically works)
------------------------+---------------------------------------------------
 Reporter:  sjamaan     |       Owner:  felix
     Type:  defect      |      Status:  new  
 Priority:  minor       |   Milestone:       
Component:  extensions  |     Version:  4.7.x
 Keywords:              |  
------------------------+---------------------------------------------------
 The trace egg calls its {{{walk-module}}} procedure with two arguments,
 but accepts exactly three arguments.

 I don't understand why it still works, though:

 {{{
 $ csi
 #;1> (use trace)
 #;2> (module foo (bar) (import chicken scheme) (define (bar x) (+ x 1)))
 #;3> (trace-module 'foo)
 ; tracing bar
 }}}

 Perhaps the extra argument gets "optimized" away because it is never used?
 I'd normally say this is a bug in the compiler, but it does warn when you
 enable scrutiny so it's probably fine to keep the compiler the way it is.

 {{{
 Index: trace.scm
 ===================================================================
 --- trace.scm   (revision 26685)
 +++ trace.scm   (working copy)
 @@ -223,7 +223,7 @@
       ((if (traced? proc) do-untrace do-trace) (list proc)))
     procs))

 -(define (walk-module mname proc warn)
 +(define (walk-module mname proc)
    (let* ((m (##sys#find-module mname))
          (exps (nth-value 1 (##sys#module-exports m))))
      (for-each
 }}}

 By the way, the trace module has no author field in the meta-file.  If you
 don't want to maintain it, maybe you can just put in "the chicken team" or
 something.

 This was found by Mario's specialization run of salmonella:
 http://parenteses.org/mario/misc/specialize-report/install/trace.html

-- 
Ticket URL: <http://bugs.call-cc.org/ticket/842>
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Chicken Scheme is a compiler for the Scheme programming language.