Concerning `(letrec ((ignore)) ...)' in line 2718 of lisp/ox.el

Concerning `(letrec ((ignore)) ...)' in line 2718 of lisp/ox.el

[Zack Piper]

Hi,

When I attempt to export an Org document using the HTML backend (and
Org backend) I get (after the initial tangle, even a normal Org
document with the word "Example" fails):

╭────
│ Wrong number of arguments: setq, 1
╰────

So I proceed to use Edebug to find out why this is happening:

Line 2718, of `lisp/ox.el' causes it.

That line is

╭────
│ (letrec ((ignore) ...))
╰────

So I tried using `M-: (letrec ((ignore)) "test"), and get the same as before.

So my question is, why is this failing now? According to `magit-blame'
these lines haven't been touched in a while, so I'm genuinely not sure
why it does this now, and, of course, is there a fix?


Thanks!

Re: Concerning `(letrec ((ignore)) ...)' in line 2718 of lisp/ox.el

[Zack Piper]

I (think) I have a recipe to reproduce this:

- Emacs 25 (emacs-25 branch from Git)
- Org mode from latest Git (make sure that there's no ELC files from
  Emacs *24*, if it uses files from Emacs 24 it works fine (bug in
  byte compiler?)).

╭────[ r.el ]
│ (add-to-list 'load-path "~/org-mode/lisp")
│ (add-to-list 'load-path "~/org-mode/contrib/lisp")
│ (require 'org)
│ 
│ (find-file "~/r.org")
│ 
│ (org-html-export-as-html)
╰────

╭────[ $ ]
│ emacs -Q -l r.el
╰────

Produces:

╭────
│ Wrong number of arguments: setq, 1
╰────

Thanks!

Re: Concerning `(letrec ((ignore)) ...)' in line 2718 of lisp/ox.el

[Kyle Meyer]

Zack Piper <zack@apertron.net> writes:

> I (think) I have a recipe to reproduce this:
>
> - Emacs 25 (emacs-25 branch from Git)
> - Org mode from latest Git (make sure that there's no ELC files from
>   Emacs *24*, if it uses files from Emacs 24 it works fine (bug in
>   byte compiler?)).
>
> ╭────[ r.el ]
> │ (add-to-list 'load-path "~/org-mode/lisp")
> │ (add-to-list 'load-path "~/org-mode/contrib/lisp")
> │ (require 'org)
> │
> │ (find-file "~/r.org")
> │
> │ (org-html-export-as-html)
> ╰────
>
> ╭────[ $ ]
> │ emacs -Q -l r.el
> ╰────
>
> Produces:
>
> ╭────
> │ Wrong number of arguments: setq, 1
> ╰────

I believe this because an odd number of arguments to setq now signals an
error:

    https://lists.gnu.org/archive/html/emacs-devel/2015-11/msg02028.html

From Emacs 25 NEWS:

    ** `setq' must now be called with an even number of arguments.  The
    earlier behavior of silently supplying a nil to the last variable when
    there was an odd number of arguments has been eliminated.

The binding

  (letrec ((ignore)

results in letrec passing an odd number of arguments to setq:

  `(let ,(mapcar #'car binders)
     ,@(mapcar (lambda (binder) `(setq ,@binder)) binders)
     ,@body))
     
Changing (ignore) to (ignore nil) should fix it.  There are several
other places in ox.el that have the same problem.  However, I don't know
if letrec should handle this instead.  Nicolas?

--
Kyle

Re: Concerning `(letrec ((ignore)) ...)' in line 2718 of lisp/ox.el

[Zack Piper]

On Fri, Dec 11, 2015 at 10:27:55AM -0500, Kyle Meyer wrote:
> 
> Zack Piper <zack@apertron.net> writes:
> 
> > I (think) I have a recipe to reproduce this:
> >
> > - Emacs 25 (emacs-25 branch from Git)
> > - Org mode from latest Git (make sure that there's no ELC files from
> >   Emacs *24*, if it uses files from Emacs 24 it works fine (bug in
> >   byte compiler?)).
> >
> > ╭────[ r.el ]
> > │ (add-to-list 'load-path "~/org-mode/lisp")
> > │ (add-to-list 'load-path "~/org-mode/contrib/lisp")
> > │ (require 'org)
> > │
> > │ (find-file "~/r.org")
> > │
> > │ (org-html-export-as-html)
> > ╰────
> >
> > ╭────[ $ ]
> > │ emacs -Q -l r.el
> > ╰────
> >
> > Produces:
> >
> > ╭────
> > │ Wrong number of arguments: setq, 1
> > ╰────
> 
> I believe this because an odd number of arguments to setq now signals an
> error:
> 
>     https://lists.gnu.org/archive/html/emacs-devel/2015-11/msg02028.html
> 
> From Emacs 25 NEWS:
> 
>     ** `setq' must now be called with an even number of arguments.  The
>     earlier behavior of silently supplying a nil to the last variable when
>     there was an odd number of arguments has been eliminated.
> 
> The binding
> 
>   (letrec ((ignore)
> 
> results in letrec passing an odd number of arguments to setq:
> 
>   `(let ,(mapcar #'car binders)
>      ,@(mapcar (lambda (binder) `(setq ,@binder)) binders)
>      ,@body))
>      
> Changing (ignore) to (ignore nil) should fix it.  There are several
> other places in ox.el that have the same problem.  However, I don't know
> if letrec should handle this instead.  Nicolas?

I submitted a patch to the emacs-devel ML which fixes this (at least
for me).
Thanks very much for tracking down this issue, Kyle!


-- 
Zack Piper <zack@apertron.net> http://apertron.net