Re: confinement's read-hash-extend gives 'unknown number radix' for all tagged forms

[Ludovic Courtès]

Hi Jelle,

Jelle Licht <jlicht@fsfe.org> skribis:

> The following does not:
>
> (use-modules (system reader confinement)
>              (language elisp parser))
> (read-hash-extend #\e (lambda (_ port) (read-elisp port)))
> (format #t "~S\n" #e(+ 1 1))
>
> ; ERROR: In procedure apply-smob/3:
> ; In procedure scm_read_number_and_radix: /tmp/confined.scm:3:20: unknown 
> number radix

It seems that the problem is that Guile-Reader’s ‘read-hash-extend’
appends hash extensions, whereas Guile’s prepends them.  See
confinement.scm:

  (set! sharp-specs
        ;; Append the module's hash extensions.  Warning: no attempt is
        ;; made to avoid conflicts.
        (append (map (lambda (chr+proc)
                       (make-token-reader (car chr+proc)
                                          (lambda (chr port read top)
                                            (apply (cdr chr+proc)
                                                   (list chr port)))))
                     (ensure-reader-hash-extensions module))
                sharp-specs))

Consequently, the default behavior for #e kicks in, and that invokes the
“token reader” for numbers.

We could change the code above to prepend.

HTH!

Ludo’.