Hi Guile devs,

This patch improves Guile's support for SRFI module names in the R6RS
and R7RS formats, i.e. (srfi :n) and (srfi n).


Copying from the commit message:

It was already possible to import an SRFI module by referencing it
as (srfi :n) which is automatically translated to (srfi srfi-n), but
this conversion was only done during import.  After this change, it's
also possible to define a library as (srfi :n) which is automatically
translated to (srfi srfi-n) during definition.

It was not possible at all to define or import SRFI module names in the
R7RS format, (srfi n), where n is a non-negative exact integer.  It is
now possible both to define and import them as such, realized through
the same kind of conversion to a canonical (srfi srfi-n) name.


The patch is attached as a MIME attachment in git format-patch format.


Note, by the way, that there was already a little bit of code in
module/ice-9/r6rs-libraries.scm to support module names like (srfi n),
but it didn't work in practice because syntax-case guards in all the
"entry points" barred the possibility of using that format.


Another note: r6rs-libraries.scm uses both 'identifier?' and the form
'sym?' which is defined as '(symbol? (syntax->datum x))'.  It's unclear
to me what the difference is and I hope my use of 'sym?' is correct.


Relevant bug reports:

- https://bugs.gnu.org/39601 (fixed)

- https://bugs.gnu.org/40371 (partly fixed)


Taylan