Re: [PATCH] Fix regex for determining image width from attribute

[Max Nikulin <manikulin@gmail.com>]

On 23/11/2021 14:46, Matt Huszagh wrote:
> Here are two patches that prioritize attr_org over other attr_
> keywords. I believe this is what you had in mind Timothy. But let me
> know if not.

> diff --git a/lisp/org.el b/lisp/org.el
> index 308bb7d51..bf5d08e09 100644
> --- a/lisp/org.el
> +++ b/lisp/org.el
> @@ -16853,13 +16853,20 @@ buffer boundaries with possible narrowing."
>     ((listp org-image-actual-width)
>      (let* ((case-fold-search t)
>             (par (org-element-lineage link '(paragraph)))
> -           (attr-re "^[ \t]*#\\+attr_.*?: +.*?:width +\\(\\S-+\\)")
> +           (attr-re (lambda (backend)
> +                      (concat "^[ \t]*#\\+attr_"
> +                              backend
> +                              ": +.*?:width +\\(\\S-+\\)")))
>             (par-end (org-element-property :post-affiliated par))
> -           ;; Try to find an attribute providing a :width.
> +           ;; If an attr_org provides a :width, use that. Otherwise,
> +           ;; use the first attribute that provides it, if any.
>             (attr-width
>              (when (and par (org-with-point-at
>                                 (org-element-property :begin par)
> -                             (re-search-forward attr-re par-end t)))
> +                             (or (re-search-forward (funcall attr-re "org")
> +                                                    par-end t)
> +                                 (re-search-forward (funcall attr-re ".*?")
> +                                                    par-end t))))

I may be wrong, but it seems both the old and the new regexps match

     #+attr_html : :width 50%

that is not a keyword due to a space before ":". The dot in the regexp 
is too permissive.

> The second patch (intended to be applied after the first) improves the
> documentation. It describes behavior that wasn't previously documented
> and removes redundant documentation between org-image-actual-width and
> org-display-inline-image--width (now only in
> org-image-actual-width). Please double check I got everything correct,
> as I haven't used all this behavior myself.

> +that is not found, use the first #+ATTR_.*:width specification.

Despite ".*" includes ": " before ":width", I would prefer explicit 
space before ":width".