Re: Problem with cond macro.

[Dirk Herrmann <dirk@ida.ing.tu-bs.de>]

On Wed, 17 Apr 2002, Keith Wright wrote:

> > From: julian@openit.de (Julian v. Bock)
> > 
> > >>>>> "PV" == Panagiotis Vossos <jacbre@internet.gr> writes:
> > 
> > PV> Ok, I just started studying macros, so I might be missing
> > PV> something obvious, but the following example from r5rs doesn't
> > PV> work correctly with guile:
> > 
> > guile> (let ((=> #f))
> > guile> 	 (cond (#t => 'ok)))
> > guile> In expression (cond (#t => #)): 
> > guile> Wrong type to apply: ok ABORT:
[...]
> R5RS> As an example. if LET and COND are defined as in section 7.3
> R5RS> then they are hygenic (as required) and the following is
> R5RS> not an error.
> R5RS>         <above example>
> 
> I take this to mean that the behaviour shown is required, and
> that furthermore the hygenic macro system exhibits the required
> behaviour.  Thus the built-in COND should work in the same
> way as the example implementation given in the R5 Report,
> even though it may be implemented more (or less) efficiently.

Well, I'm not sure I understand all of this:  What about the following:

(define => #f)
(cond (#t => 'ok))

Should this also deliver 'ok ?  It doesn't seem to with the current
implementation of syncase.

Best regards,
Dirk Herrmann


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