> From: Dirk Herrmann <[EMAIL PROTECTED]>
> Date: Fri, 6 Apr 2001 18:33:48 +0200 (MEST)
>
> On Fri, 6 Apr 2001, Martin Grabmueller wrote:
>
> > > From: Mikael Djurfeldt <[EMAIL PROTECTED]>
> > > Date: 05 Apr 2001 01:12:28 +0200
> > >
> > > Martin Grabmueller <[EMAIL PROTECTED]> writes:
> > >
> > > > according to R5RS, literally entered vectors do not evaluate to
> > > > themselves and must always be quoted. Guile does not detect this
> > > > error:
> > > >
> > > > guile> #(as)
> > > > #(as)
> > > >
> > > > Should this be fixed, and can it be fixed easily?
> > >
> > > It should be fixed and it is easy to fix. We only need to remove a
> > > case in a switch at the top of the evaluator.
> >
> > I have done that, but not committed yet. As I have never touched the
> > evaluator before, I am not sure if the attached patch is sufficient.
> > Also, R5RS only defines ``Numerical constants, string constants,
> > character constants and boolean constants'' (R5RS 4.1.2) as
> > self-evaluating, so the following cases should be removed, too:
> >
> > case scm_tc7_smob:
> > case scm_tcs_closures:
> > case scm_tc7_cclo:
> > case scm_tc7_pws:
> > case scm_tcs_subrs:
> >
> > and the `struct' part of the following:
>
> Unfortunately, things are not that easy. Bignums, real and complex
> numbers are realized as smobs. Thus, if you want that all numerical
> constants (and not just immediate numbers) evaluate to themselves, you
> have to be a little bit more careful here.
Hmm. I see. So what's the way to go?
> Actually, I don't understand the requirement that vectors don't evaluate
> to themselves. The fact that it is said explicitly in R5RS is an
> indication that there must be a good reason for it, but I don't see why.
I suppose it's for symmetry with lists. Vectors can be used in
syntax-case templates like lists, and also in quasiquotations. But
that's just a theory, which is by me and is completely mine...
Regards,
'martin
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