[Chicken-janitors] Re: #511: Expander problem with "declare" triggered by snowtar

[Chicken Trac]

#511: Expander problem with "declare" triggered by snowtar
-----------------------+----------------------------------------------------
  Reporter:  sjamaan   |       Owner:  felix                       
      Type:  defect    |      Status:  assigned                    
  Priority:  critical  |   Milestone:  4.7.0                       
 Component:  expander  |     Version:  4.6.x                       
Resolution:            |    Keywords:  declare, macro-expanded code
-----------------------+----------------------------------------------------
Changes (by sjamaan):

  * owner:  sjamaan => felix
  * status:  new => assigned


Comment:

 Turns out this has nothing to do with "declare" after all, but it was a
 bug in my patch for #379 (forgot to rename "-")

 It turns out that even renaming it properly does not help - because the
 library imports an global identifier called "{{{-}}}", that will always be
 used. If this is a bug, we should really look at that! I suppose it may
 not really be a bug as syntax-rules is a macro-generating macro; it would
 have to have some way to refer to the definition of {{{-}}} at the
 definition site of syntax-rules, not at the definition site of the macro
 that it generates (I hope this makes sense... *My* head almost
 exploded...).

 Another example is that I was unable to rename "length" in such a way that
 it couldn't be captured like this:

 {{{
 (module capture (length)
   (import chicken (only scheme define car))
   (define (length x)
     (car x)))

 (module foo (bar)
   (import chicken scheme capture)
   (define-syntax def
     (syntax-rules ()
       ((_ name value ...)
        (define (name) (list value ...)))))
   (def bar 1))
 }}}

 I had to work around that by adding a "safe" {{{##sys#length}}} to
 {{{library.scm}}}. The minus I simply changed to plus, and added -1 to the
 value. Alternatively, I could've done the same as for length, to add
 {{{##sys#-}}} to {{{library.scm}}}.

 These immediate bugs in syntax-rules have been fixed in changeset 0eb8724
 of the {{{expander-simplifications}}} branch; I've also removed a couple
 of unused local definitions there.

 We should check that the non-{{{##sys#}}}-prefixed identifiers like the
 special forms {{{and}}} and such -- but also the free identifiers like
 {{{compare}}} and such! --

-- 
Ticket URL: <http://bugs.call-cc.org/ticket/511#comment:2>
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