bug#47875: Elisp reader doesn't handle keywords

bug#47875: Elisp reader doesn't handle keywords

[Leo Prikler]

Hi Guilers,

Using Guile 3.0.5, the elisp reader does not seem to support keywords
written in Elisp's preferred prefix-style notation (:keyword).

scheme@(guile-user)> ,L elisp
Happy hacking with Emacs Lisp!  To switch back, type `,L scheme'.
elisp@(guile-user)> :keyword
ice-9/boot-9.scm:1669:16: In procedure raise-exception:
Unbound variable: :keyword

Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
elisp@(guile-user) [1]> ,q
elisp@(guile-user)> (funcall (@ (guile) symbol->keyword) 'keyword)
$1 = #:keyword

Meanwhile in Emacs M-: :keyword yields :keyword.  Using Scheme-style
keywords also does not work:

elisp@(guile-user)> #:keyword
While compiling expression:
uninterned symbol cannot be saved to object file #<uninterned-symbol
keyword 7fb39fa4b5e0>

I think Guile should produce keyword objects for the former, so that we
don't need to talk about the latter.

Regards,
Leo

bug#47875: Elisp reader doesn't handle keywords

[Taylan Kammer]

This seems to have been fixed in the wip-elisp branch.

Note that the branch is a couple years old.  There's a version
of the branch by Ricardo Wurmus (rekado) that's been rebased on
a newer version of Guile, though still not on 3.0:

https://git.elephly.net/?p=software/guile.git;a=shortlog;h=refs/heads/wip-elisp


- Taylan

bug#47875: Elisp reader doesn't handle keywords

[Ivan Sokolov]

Leo Prikler <leo.prikler@student.tugraz.at> writes:

> Using Guile 3.0.5, the elisp reader does not seem to support keywords
> written in Elisp's preferred prefix-style notation (:keyword).
>
> Meanwhile in Emacs M-: :keyword yields :keyword.  Using Scheme-style
> keywords also does not work:
>
> I think Guile should produce keyword objects for the former, so that we
> don't need to talk about the latter.

In Scheme keywords and symbols are separate entities, but in Elisp
keywords are just self-quoted symbols. I think your solution will cause
problems with Elisp algorithms that expect keywords to be symbolp.

bug#47875: Elisp reader doesn't handle keywords

[Leo Prikler]

Am Samstag, den 05.06.2021, 18:51 +0300 schrieb Ivan Sokolov:
> In Scheme keywords and symbols are separate entities, but in Elisp
> keywords are just self-quoted symbols. I think your solution will
> cause problems with Elisp algorithms that expect keywords to be
> symbolp.
You could define Elisp symbolp as 
(lambda (thing)
  (or (funcall (@ (guile) symbol?) thing)
      (funcall (@ (guile) keyword?) thing)))
but perhaps there's an even faster way to check this property.
The other way round – using Emacs keywords as Scheme symbols – will not
perform well if you think about Emacs code calling a Scheme function
that expects keywords.

Regards,
Leo

bug#47875: Elisp reader doesn't handle keywords

[Ivan Sokolov]

Leo Prikler <leo.prikler@student.tugraz.at> writes:
> You could define Elisp symbolp as
> (lambda (thing)
>   (or (funcall (@ (guile) symbol?) thing)
>       (funcall (@ (guile) keyword?) thing)))
You are right, I haven't thought about changing the implementaion of
symbolp.

> but perhaps there's an even faster way to check this property.
Use guile-primitive instead of guile-ref? Both symbol? and keyword? are
primitives.