Re: Links & images with different attributes in the same paragraph

[Max Nikulin <manikulin@gmail.com>]

On 05/12/2023 20:46, Ihor Radchenko wrote:
> 
> We definitely need something to fine-tune export properties inline.
> However, I am skeptical about using links for this purpose in Org
> proper, not individual user configs.

Sometimes links are really links, however some links require some 
tuning. Global style or custom export backend that modifies all links is 
not always suitable.

Perhaps special :href values may be added to allow just decorations 
without hyperlinks.

> I believe that the right way to go here is what we previously discussed
> as inline special block equivalent. That way, we will not need to create
> workarounds with special link type.

It is limitation of top-down parser that object of the same time can not 
be nested, so I am unsure if special blocks would be solution in all cases.

I have added a hack to allow definitions of links or their attributes 
outside of paragraphs. Noweb and source code blocks allow it. Perhaps is 
should be implemented as a filter to avoid tricks to get noexport source 
blocks

---- 8< ----
A link defined in a source block
[[wrap:<<org-mode>> :attr_html ":class org"][Org mode]]

#+name: org-mode
#+begin_src elisp :exports none
:href "https://orgmode.org"
:attr_html ":title Org Mode — Your life in plain text"
#+end_src
---- >8 ----

(defun nm/org-link-wrap-path-to-props (path &optional info)
   (let* ((with-broken-links (plist-get info :with-broken-links))
	 (org-babel-noweb-error-all-langs
	  (if (not with-broken-links)
	      t
	    ;; TODO Handle `mark', currently errors are ignored.
	    org-babel-noweb-error-all-langs))
	 (expanded
	  (org-babel-expand-noweb-references
	   (list "elisp" path '(:noweb-prefix "no"))
	   ;; Allow noweb references to code blocks
	   ;; having ":exports none".
	   (plist-get info :input-buffer))))
     (read(concat "(" expanded ")"))))

(defun nm/org-link-wrap-assert-href (props path)
   (let ((href (plist-get props :href)))
     (pcase href
       ((pred null) (signal
		    'org-link-broken
		    (list (format "no :href property in `%s'" path))))
       ((pred stringp) href)
       ((pred symbolp) (symbol-name href))
       (_ (signal
	  'org-link-broken
	  (list (format "Invalid :href type in `%s'" path)))))))

(defun nm/org-link-wrap-copy-props (props link)
   (while props
     (let ((name (pop props))
	  (value (pop props))
	  (case-fold-search t))
       (org-element-put-property
        link
        name
        ;; `org-element--collect-affiliated-keywords'
        (if (string-match-p "\\`:attr_" (symbol-name name))
	   (append (org-element-property name link) (list value))
	 value)))))

(defun nm/org-link-wrap-export
     (path description backend info)
   (let* ((props-all (nm/org-link-wrap-path-to-props path info))
	 (href (nm/org-link-wrap-assert-href props-all path))
	 ;; `org-plist-delete' removes other duplicated keys as well.
	 (props (map-delete props-all :href))
	 ;; Taken from `org-link-open-from-string'.
	 (link (with-temp-buffer
		 (let ((org-inhibit-startup nil))
		   (insert "[[" (org-link-escape href) "]]")
		   (org-mode)
		   (goto-char (point-min))
		   (org-element-link-parser)))))
     (nm/org-link-wrap-copy-props props link)
     (when description
       (org-element-set-contents link description))
     (org-no-properties
      (org-export-data-with-backend link backend info))))

(defun nm/org-link-wrap-follow (path arg)
   (let* ((props (nm/org-link-wrap-path-to-props path))
	 (href (nm/org-link-wrap-assert-href props path)))
     (org-link-open-from-string
      (concat "[[" (org-link-escape href) "]]")
      arg)))

(org-link-set-parameters
  "wrap"
  :follow #'nm/org-link-wrap-follow
  :export #'nm/org-link-wrap-export)