Re: [PATCH] Enhance org-html--build-meta-info

[TEC <tecosaur@gmail.com>]

Jens Lechtenboerger <lechten@wi.uni-muenster.de> writes:

>> Currently the only element handled differently to
>> `org-html-encode-plain-text' is "author". I don't know why so I 
>> don't
>> want to touch it.
>
> I believe that was also the previous conclusion.  However, as 
> this
> is not documented, maybe now could be the chance to change this?

Hmm. Maybe, it sounds like some tests may be in order.

> I must I admit that I do not fully understand your approach.
>
> Why do you treat keywords and description differently (with
> description in org-html-meta-tags and keywords in
> org-html--build-meta-info)?

Ooops, that should have been in org-html-meta-tags as the rest 
are.
[Fixed]

> Why do you pass _title into the lambda expressions in
> org-html-meta-tags when it is never used?  Currently, the 
> variable
> org-html-meta-tags does not seem user-friendly to me.

Title and author just seemed like the most likely useful 
information for
customisation. It would be nice if it looked less boiler-plate-y, 
but
I'm not sure what the best approach for that would be, and it's 
already
miles better than the current.
If you have any ideas, please let me know.

> Also, in org-html--build-meta-info you call
> org-html-encode-plain-text with two arguments, but it just 
> accepts
> one.

? No I don't.

> Best wishes
> Jens

Hope that clarifies things a bit,

Timothy.


------
Moved the keyword in with the rest.



From 889ae918aed267417825d565df9135221dae16b1 Mon Sep 17 00:00:00 
2001
From: TEC <tec@tecosaur.com>
Subject: [PATCH] lisp/ox-html.el: make html meta func nicer

* lisp/ox-html.el (org-html--build-meta-info): Multi-line repeated
structure extracted to new function `org-html--build-meta-entry'.
The opportunity was taken to extract most metadata info to custom
variable `org-html-meta-tags', allowing for easy end-user 
modification.
---
 lisp/ox-html.el | 114 
 +++++++++++++++++++++++++++---------------------
 1 file changed, 64 insertions(+), 50 deletions(-)

diff --git a/lisp/ox-html.el b/lisp/ox-html.el
index d2f24f5c6..46195b0e0 100644
--- a/lisp/ox-html.el
+++ b/lisp/ox-html.el
@@ -1425,6 +1425,31 @@ not be modified."

 ;;;; Template :: Styles

+(defcustom org-html-meta-tags
+  '((lambda (_title author _info)
+      (when (org-string-nw-p author)
+	(list "name" "author" author)))
+    (lambda (_title _author info)
+      (when (org-string-nw-p (plist-get info :description))
+	(list "name" "description"
+	      (plist-get info :description))))
+    (lambda (_title _author info)
+      (when (org-string-nw-p (plist-get info :keywords))
+	(list "keywords" (plist-get info :keywords))))
+    ("name" "generator" "Org Mode"))
+  "A list of arguments to be passed to 
`org-html--build-meta-entry'.
+Each argument can either be an list which is applied, or a 
function which
+generates such a list with signature (TITLE AUTHOR INFO) where 
TITLE and AUTHOR
+are strings, and INFO a communication plist."
+  :group 'org-export-html
+  :package-version '(Org . "9.5")
+  :type '(repeat
+	  (choice
+	   (list (string :tag "Meta label")
+		 (string :tag "label value")
+		 (string :tag "Content value"))
+	   function)))
+
 (defcustom org-html-head-include-default-style t
   "Non-nil means include the default style in exported HTML 
   files.
 The actual style is defined in `org-html-style-default' and
@@ -1835,23 +1860,31 @@ INFO is a plist used as a communication 
channel."
 \f
 ;;; Template

+(defun org-html--build-meta-entry (label identity &optional 
content-format &rest content-formatters)
+  "Construct <meta> tag with LABEL=\"IDENTITY\" and content from 
CONTENT-FORMAT and CONTENT-FORMATTER."
+  (concat "<meta "
+	  (format "%s=\"%s" label identity)
+	  (when content-format
+	    (concat "\" content=\""
+		    (replace-regexp-in-string
+		     "\"" "&quot;"
+		     (org-html-encode-plain-text
+		      (if content-formatters
+			  (apply #'format content-format content-formatters)
+			content-format)))))
+	  "\" />\n"))
+
 (defun org-html--build-meta-info (info)
   "Return meta tags for exported document.
 INFO is a plist used as a communication channel."
-  (let* ((protect-string
-          (lambda (str)
-            (replace-regexp-in-string
-             "\"" "&quot;" (org-html-encode-plain-text str))))
-         (title (org-export-data (plist-get info :title) info))
+  (let* ((title (org-html-encode-plain-text (plist-get info 
:title) info))
          ;; Set title to an invisible character instead of 
          leaving it
          ;; empty, which is invalid.
          (title (if (org-string-nw-p title) title "&lrm;"))
          (author (and (plist-get info :with-author)
                       (let ((auth (plist-get info :author)))
-			;; Return raw Org syntax.
+         ;; Return raw Org syntax.
                         (and auth (org-element-interpret-data 
                         auth)))))
-         (description (plist-get info :description))
-         (keywords (plist-get info :keywords))
          (charset (or (and org-html-coding-system
                            (fboundp 'coding-system-get)
                            (coding-system-get 
                            org-html-coding-system
@@ -1863,50 +1896,31 @@ INFO is a plist used as a communication 
channel."
 	(concat "<!-- "
 		(plist-get info :html-metadata-timestamp-format)
 		" -->\n")))
-     (format
-      (if (org-html-html5-p info)
-	  (org-html-close-tag "meta" "charset=\"%s\"" info)
-	(org-html-close-tag
-	 "meta" "http-equiv=\"Content-Type\" 
      content=\"text/html;charset=%s\""
-	 info))
-      charset) "\n"
+
+     (if (org-html-html5-p info)
+	 (org-html--build-meta-entry "charset" charset)
+       (org-html--build-meta-entry "http-equiv" "Content-Type"
+				   (concat "text/html;charset=" charset)))
+
      (let ((viewport-options
-	    (cl-remove-if-not (lambda (cell) (org-string-nw-p (cadr 
         cell)))
-			      (plist-get info :html-viewport))))
-       (and viewport-options
-	    (concat
-	     (org-html-close-tag
-	      "meta"
-	      (format "name=\"viewport\" content=\"%s\""
-		      (mapconcat
-		       (lambda (elm) (format "%s=%s" (car elm) (cadr 
                elm)))
-		       viewport-options ", "))
-	      info)
-	     "\n")))
+            (cl-remove-if-not (lambda (cell) (org-string-nw-p 
(cadr cell)))
+                              (plist-get info :html-viewport))))
+       (if viewport-options
+           (org-html--build-meta-entry "name" "viewport"
+                                       (mapconcat
+                                        (lambda (elm) (format 
"%s=%s" (car elm) (cadr elm)))
+                                        viewport-options ", "))))
+
      (format "<title>%s</title>\n" title)
-     (org-html-close-tag "meta" "name=\"generator\" content=\"Org 
      mode\"" info)
-     "\n"
-     (and (org-string-nw-p author)
-	  (concat
-	   (org-html-close-tag "meta"
-			       (format "name=\"author\" content=\"%s\""
-				       (funcall protect-string author))
-			       info)
-	   "\n"))
-     (and (org-string-nw-p description)
-	  (concat
-	   (org-html-close-tag "meta"
-			       (format "name=\"description\" content=\"%s\"\n"
-				       (funcall protect-string description))
-			       info)
-	   "\n"))
-     (and (org-string-nw-p keywords)
-	  (concat
-	   (org-html-close-tag "meta"
-			       (format "name=\"keywords\" content=\"%s\""
-				       (funcall protect-string keywords))
-			       info)
-	   "\n")))))
+
+     (apply #'concat
+	    (mapcar
+	     (lambda (form)
+	       (when (functionp form)
+		 (setq form (funcall form title author info)))
+	       (when form
+		 (apply #'org-html--build-meta-entry form)))
+	     org-html-meta-tags)))))

 (defun org-html--build-head (info)
   "Return information for the <head>..</head> of the HTML output.
--
2.28.0