Subject: Re: bug#40371: [R7RS] Guile does not accept library name parts that are non-negative exact integers

From: Marc Nieper-Wißkirchen <[email-masked]>
Date: Thu, 2 Apr 2020 21:47:19 +0200

Am Do., 2. Apr. 2020 um 21:05 Uhr schrieb Andy Wingo <[email-masked]>:

> In the concrete case of the SRFI modules, importing e.g. (srfi 9) works
> AFAIU.  Does this not work for you?
>

I use Guile 3.9.1.

I can do (import (srfi srfi-9)), but I can't do (import (srfi 9)).

That latter yields the error:

source expression failed to match any pattern in form (srfi 9).

>
> I think that allowing numbers as module name components, beyond the SRFI
> modules, is not currently a good idea for Guile.  I had a look at it and
> it's a bit too intrusive.

If numbers are not allowed, Guile will be severely crippled with respect to
R7RS code. Most SRFIs are distributed under the name `(srfi NNN)' so many
R7RS programs intended to be portable will try to import libraries of the
form, say `(srfi 9)' and Guile would complain.

`cond-expand' is not helpful here in general as an R7RS top-level program
has to start with an import and cannot start with some `(cond-expand (guile
...))'. (Besides, `cond-expand' has its own problems:
https://lists.gnu.org/archive/html/bug-guile/2020-03/msg00097.html).

As a quick-and-dirty workaround, I would suggest that the Guiles
(syntax-case?) parser of library names accepts numbers as module name
components but treats them internally as symbols (say, by prefixing them
with a colon) so that the main module code doesn't have to be touched. The
locator for library code in the file system will then have to look for a
filenname with a colon and without.

Marc

>
> Andy
>
> On Wed 01 Apr 2020 12:47, Marc Nieper-Wißkirchen <[email-masked]>
> writes:
>
> > An R7RS library name consists of parts, where each part is either a
> symbol or
> > a non-negative exact integer. Guile doesn't support the latter ones.
> >
> > This is unfortunate as the implementation of a SRFI NNN is usually
> delivered
> > in form of a library named (srfi NNN).
> >
> > When this is corrected, for interoperability, it would be great if Guile
> offers
> > the included SRFIs not only under the name (srfi srfi-NNN) but also under
> > (srfi NNN).
> >
> > Thanks,
> >
> > Marc
>