Re: Buffer local value lost when exporting? (was Evaluate all org tables in file before exporting)

[Nicolas Goaziou <mail@nicolasgoaziou.fr>]

Hello,

Eric S Fraga <e.fraga@ucl.ac.uk> writes:

> On Thursday, 12 May 2016 at 15:54, Kaushal Modi wrote:
>> Hi all,
>>
>> I almost have a squeaky clean solution to this thanks to the hint
>> provided by someone on emacs.SE (
>> http://emacs.stackexchange.com/a/22215/115 ).
>>
>> But in the process, I seem to have stumbled upon a bug.. the buffer
>> local value of variables are not respected at the time of exports.
>
> It's not a bug but a known design feature.  A new buffer is created as
> part of the export process and this buffer does not inherit local
> variable values.  What you need to do is tell org to set specific
> variables upon export.  You can use the #+BIND: directive to do this.
>
> I don't know where this is documented but there is mention of whether to
> allow this to happen in the org info manual:
>
>    If ‘org-export-allow-bind-keywords’ is non-‘nil’, Emacs variables can
>    become buffer-local during export by using the BIND keyword.  Its
>    syntax is ‘#+BIND: variable value’.  This is particularly useful for
>    in-buffer settings that cannot be changed using specific keywords.
>
> Give this a try.

For completeness, export process actually inherits some buffer local
values. See `org-export--generate-copy-script', in particular

  ;; Copy specific buffer local variables and variables set
  ;; through BIND keywords.
  ,@(let ((bound-variables (org-export--list-bound-variables))
          vars)
      (dolist (entry (buffer-local-variables (buffer-base-buffer)) vars)
        (when (consp entry)
          (let ((var (car entry))
                (val (cdr entry)))
            (and (not (memq var org-export-ignored-local-variables))
                 (or (memq var
                           '(default-directory
                              buffer-file-name
                              buffer-file-coding-system))
                     (assq var bound-variables)
                     (string-match "^\\(org-\\|orgtbl-\\)"
                                   (symbol-name var)))
                 ;; Skip unreadable values, as they cannot be
                 ;; sent to external process.
                 (or (not val) (ignore-errors (read (format "%S" val))))
                 (push `(set (make-local-variable (quote ,var))
                             (quote ,val))
                       vars))))))

So basically, it copies all Org related variables, default directory,
buffer-file-name buffer-file-coding-system and any variable defined as
a BIND keyword, provided their value is `read'-able (e.g., not a hash
table).


Regards,

-- 
Nicolas Goaziou