[BUG] Can't export variable named "nil" to Texinfo

[BUG] Can't export variable named "nil" to Texinfo

[8dcc]

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Hello,

I can export the following "Variable" to Texinfo with
`org-texinfo-export-to-texinfo':

  - Variable: my-name ::

    Content...

Results in the following .texi:

  @defvar my-name
  Content@dots{}
  @end defvar

However, if the variable is named "nil" (without the quotes), the
variable name is not exported, and a warning is generated when
processing the .texi file:

  - Variable: nil ::

    Content...

Results in:

  @defvar
  Content@dots{}
  @end defvar

When running `makeinfo --pdf file.texi':

  file.texi:50: warning: missing category for @defvar

I saw the "Variable" to "@defvar" conversion is made with
`org-texinfo--definition-command-alist' in `ox-texinfo.el', which then
gets used in `org-texinfo--match-definition' through the
regexp. However, I was not able to see why a "nil" string isn't
processed.

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Re: [BUG] Can't export variable named "nil" to Texinfo

[Ihor Radchenko]

8dcc <8dcc.git@gmail.com> writes:

> However, if the variable is named "nil" (without the quotes), the
> variable name is not exported, and a warning is generated when
> processing the .texi file:
>
>   - Variable: nil ::
>
>     Content...
>
> Results in:
>
>   @defvar
>   Content@dots{}
>   @end defvar

Confirmed.
Although, I am not sure if this is worth fixing.

The reason why you observe this behavior is in implementation detail in
ox-texinfo - `org-texinfo--split-definition' parses description lists,
replacing them with

#+attr_texinfo: :options name
#+begin_defvar
...
#+end_defvar

block, and it happens to be that :options nil is treated specially by
Org export (See `org-texinfo-special-block' calling
`org-export-read-attribute')). "nil" is not read literally, but is
instead interpreted as removing the option value - when one needs to
combine multiple attributes and override previous setting.

In theory, we may fix this edge case just for ox-texinfo. But is it
worth it? Do you _really_ have variable name "nil"?

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
or support my work at <https://liberapay.com/yantar92>

Re: [BUG] Can't export variable named "nil" to Texinfo

[8dcc]

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Ihor Radchenko <yantar92@posteo.net> writes:

> It happens to be that :options nil is treated specially by Org
> export. "nil" is not read literally, but is instead interpreted as
> removing the option value - when one needs to combine multiple
> attributes and override previous setting.

I see. I didn't know about "combining attributes", but I guess that
makes sense.

> In theory, we may fix this edge case just for ox-texinfo. But is it
> worth it?

I am not sure if it's worth fixing, specially since I don't know any
possible alternatives apart from using another keyword for specifying
this "attribute combination" (again, not sure how that works). Either
way, modifying existing behavior doesn't sound too good to me, specially
considering the amount of "nil" variables :)

> Do you _really_ have variable name "nil"?

Yes, I was not looking for this error, I didn't even know why it
happened before you told me. I am using Org to write the manual for my
Lisp interpreter, and I am exporting it to Texinfo. I wanted to explain
how `nil' works, and when it's used.

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Re: [BUG] Can't export variable named "nil" to Texinfo

[Ihor Radchenko]

8dcc <8dcc.git@gmail.com> writes:

>> Do you _really_ have variable name "nil"?
>
> Yes, I was not looking for this error, I didn't even know why it
> happened before you told me. I am using Org to write the manual for my
> Lisp interpreter, and I am exporting it to Texinfo. I wanted to explain
> how `nil' works, and when it's used.

Fixed, on main.
I made it so that ox-texinfo can handle nil values normally by working
around `org-export-read-attribute'.
https://git.savannah.gnu.org/cgit/emacs/org-mode.git/commit/?id=da0f6eff75

It will still be impossible to do something like
#+begin_defvar :options nil
...
#+end_defvar

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
or support my work at <https://liberapay.com/yantar92>