Remove `org-get-tags-string'

* lisp/org.el (org-get-tags-string): Move to "org-compat".
(org-make-tag-string): New function
(org-set-tags-to):
(org-set-tags):
(org-set-current-tags-overlay):
(org-entry-properties):
(org-agenda-prepare-buffers):
* lisp/org-mouse.el (org-mouse-set-tags):
* lisp/ox-ascii.el (org-ascii--build-title):
* lisp/ox-beamer.el (org-beamer-select-environment):
* lisp/ox-latex.el (org-latex-format-inlinetask-default-function):
* lisp/ox-md.el (org-md-headline):
(org-md--build-toc):
* lisp/ox-texinfo.el (org-texinfo-format-headline-default-function):
(org-texinfo-format-inlinetask-default-function):
* contrib/lisp/ox-groff.el (org-groff-headline):
(org-groff-inlinetask): Use new function.
* lisp/org-compat.el (org-get-tags-string): New function.

contrib/lisp/ox-groff.el

@@ -977,8 +977,7 @@ holding contextual information."
                        (when priority (format " [\\#%c] " priority))
                        text
                        (when tags
-                         (format " \\fC:%s:\\fP "
-                                 (mapconcat 'identity tags ":"))))))
+                         (format " \\fC%s\\fP " (org-make-tag-string tags))))))
          (full-text-no-tag
           (if (functionp org-groff-format-headline-function)
               ;; User-defined formatting function.
@@ -1120,8 +1119,7 @@ holding contextual information."
                (when todo (format "\\fB%s\\fP " todo))
                (when priority (format " [\\#%c] " priority))
                title
-               (when tags (format " \\fC:%s:\\fP "
-                                  (mapconcat 'identity tags ":"))))))
+               (when tags (format " \\fC%s\\fP " (org-make-tag-string tags))))))
          (format (concat "\n.DS I\n"
                          "%s\n"
                          ".sp"

lisp/org-compat.el

@@ -395,6 +395,11 @@ use of this function is for the stuck project list."
   (declare (obsolete "use `org-get-tags' instead." "Org 9.2"))
   (org-get-tags pos 'local))
 
+(defun org-get-tags-string ()
+  "Get the TAGS string in the current headline."
+  (declare (obsolete "use `org-make-tag-string' instead." "Org 9.2"))
+  (org-make-tag-string (org-get-tags nil t)))
+
 ;;;; Obsolete link types
 
 (eval-after-load 'org

lisp/org-mouse.el

@@ -448,7 +448,7 @@ SCHEDULED: or DEADLINE: or ANYTHINGLIKETHIS:"
     ;; set new tags if any
     (when tags
       (end-of-line)
-      (insert " :" (mapconcat 'identity tags ":") ":")
+      (insert " " (org-make-tag-string tags))
       (org-set-tags nil t))))
 
 (defun org-mouse-insert-checkbox ()

lisp/org.el

@@ -14211,10 +14211,9 @@ If DATA is nil or the empty string, all tags are removed."
   (let ((data
 	 (pcase (if (stringp data) (org-trim data) data)
 	   ((or `nil "") nil)
-	   ((pred listp) (format ":%s:" (mapconcat #'identity data ":")))
+	   ((pred listp) (org-make-tag-string data))
 	   ((pred stringp)
-	    (format ":%s:"
-		    (mapconcat #'identity (org-split-string data ":+") ":")))
+	    (org-make-tag-string (org-split-string data ":+")))
 	   (_ (error "Invalid tag specification: %S" data)))))
     (org-with-wide-buffer
      (org-back-to-heading t)
@@ -14263,7 +14262,7 @@ When JUST-ALIGN is non-nil, only align tags."
 	      (org-set-tags nil t)
 	      (end-of-line))
             (message "All tags realigned to column %d" org-tags-column))
-	(let* ((current (org-get-tags-string))
+	(let* ((current (org-make-tag-string (org-get-tags nil t)))
 	       (tags
 		(if just-align current
 		  ;; Get a new set of tags from the user.
@@ -14436,7 +14435,7 @@ Also insert END."
 
 (defun org-set-current-tags-overlay (current prefix)
   "Add an overlay to CURRENT tag with PREFIX."
-  (let ((s (concat ":" (mapconcat 'identity current ":") ":")))
+  (let ((s (org-make-tag-string current)))
     (put-text-property 0 (length s) 'face '(secondary-selection org-tag) s)
     (org-overlay-display org-tags-overlay (concat prefix s))))
 
@@ -14642,15 +14641,11 @@ Returns the new tags string, or nil to not change the current settings."
 	  (mapconcat 'identity current ":")
 	nil))))
 
-(defun org-get-tags-string ()
-  "Get the TAGS string in the current headline."
-  (unless (org-at-heading-p t)
-    (user-error "Not on a heading"))
-  (save-excursion
-    (beginning-of-line 1)
-    (if (looking-at ".*[ \t]\\(:[[:alnum:]_@#%:]+:\\)[ \t]*$")
-	(match-string-no-properties 1)
-      "")))
+(defun org-make-tag-string (tags)
+  "Return string associated to TAGS.
+TAGS is a list of strings."
+  (if (null tags) ""
+    (format ":%s:" (mapconcat #'identity tags ":"))))
 
 (defun org--get-local-tags ()
   "Return list of tags for the current headline.
@@ -15031,14 +15026,15 @@ strings."
 		    props)
 	      (when specific (throw 'exit props)))
 	    (when (or (not specific) (string= specific "TAGS"))
-	      (let ((value (org-string-nw-p (org-get-tags-string))))
-		(when value (push (cons "TAGS" value) props)))
+	      (let ((tags (org-get-tags nil t)))
+		(when tags
+		  (push (cons "TAGS" (org-make-tag-string tags))
+			props)))
 	      (when specific (throw 'exit props)))
 	    (when (or (not specific) (string= specific "ALLTAGS"))
-	      (let ((value (org-get-tags)))
-		(when value
-		  (push (cons "ALLTAGS"
-			      (format ":%s:" (mapconcat #'identity value ":")))
+	      (let ((tags (org-get-tags)))
+		(when tags
+		  (push (cons "ALLTAGS" (org-make-tag-string tags))
 			props)))
 	      (when specific (throw 'exit props)))
 	    (when (or (not specific) (string= specific "BLOCKED"))
@@ -17915,7 +17911,7 @@ When a buffer is unmodified, it is just killed.  When modified, it is saved
 	(pall '(:org-archived t :org-comment t))
 	(inhibit-read-only t)
 	(org-inhibit-startup org-agenda-inhibit-startup)
-	(rea (concat ":" org-archive-tag ":"))
+	(rea (org-make-tag-string (list org-archive-tag)))
 	re pos)
     (setq org-tag-alist-for-agenda nil
 	  org-tag-groups-alist-for-agenda nil)

lisp/ox-ascii.el

@@ -671,8 +671,7 @@ possible.  It doesn't apply to `inlinetask' elements."
 		    (plist-get info :with-tags)
 		    (let ((tag-list (org-export-get-tags element info)))
 		      (and tag-list
-			   (format ":%s:"
-				   (mapconcat 'identity tag-list ":"))))))
+			   (org-make-tag-string tag-list)))))
 	 (priority
 	  (and (plist-get info :with-priority)
 	       (let ((char (org-element-property :priority element)))

lisp/ox-beamer.el

@@ -1076,11 +1076,11 @@ aid, but the tag does not have any semantic meaning."
 	 (org-use-fast-tag-selection t)
 	 (org-fast-tag-selection-single-key t))
     (org-set-tags)
-    (let ((tags (or (ignore-errors (org-get-tags-string)) "")))
+    (let ((tags (org-get-tags nil t)))
       (cond
        ;; For a column, automatically ask for its width.
        ((eq org-last-tag-selection-key ?|)
-	(if (string-match ":BMCOL:" tags)
+	(if (member "BMCOL" tags)
 	    (org-set-property "BEAMER_col" (read-string "Column width: "))
 	  (org-delete-property "BEAMER_col")))
        ;; For an "againframe" section, automatically ask for reference
@@ -1096,7 +1096,8 @@ aid, but the tag does not have any semantic meaning."
 	   (read-string "Frame reference (*Title, #custom-id, id:...): "))
 	  (org-set-property "BEAMER_act"
 			    (read-string "Overlay specification: "))))
-       ((string-match (concat ":B_\\(" (mapconcat 'car envs "\\|") "\\):") tags)
+       ((let ((tags-re (concat "B_" (regexp-opt (mapcar #'car envs) t))))
+	  (cl-some (lambda (tag) (string-match tags-re tag)) tags))
 	(org-entry-put nil "BEAMER_env" (match-string 1 tags)))
        (t (org-entry-delete nil "BEAMER_env"))))))
 

lisp/ox-latex.el

@@ -2132,8 +2132,9 @@ See `org-latex-format-inlinetask-function' for details."
 		 (when priority (format "\\framebox{\\#%c} " priority))
 		 title
 		 (when tags
-		   (format "\\hfill{}\\textsc{:%s:}"
-			   (mapconcat #'org-latex--protect-text tags ":"))))))
+		   (format "\\hfill{}\\textsc{%s}"
+			   (org-make-tag-string
+			    (mapcar #'org-latex--protect-text tags)))))))
     (concat "\\begin{center}\n"
 	    "\\fbox{\n"
 	    "\\begin{minipage}[c]{.6\\textwidth}\n"

lisp/ox-md.el

@@ -211,8 +211,7 @@ a communication channel."
 	   (tags (and (plist-get info :with-tags)
 		      (let ((tag-list (org-export-get-tags headline info)))
 			(and tag-list
-			     (format "     :%s:"
-				     (mapconcat 'identity tag-list ":"))))))
+			     (concat "     " (org-make-tag-string tag-list))))))
 	   (priority
 	    (and (plist-get info :with-priority)
 		 (let ((char (org-element-property :priority headline)))
@@ -589,10 +588,8 @@ contents according to the current headline."
 			  (org-export-get-reference headline info))))
 	     (tags (and (plist-get info :with-tags)
 			(not (eq 'not-in-toc (plist-get info :with-tags)))
-			(let ((tags (org-export-get-tags headline info)))
-			  (and tags
-			       (format ":%s:"
-				       (mapconcat #'identity tags ":")))))))
+			(org-make-tag-string
+			 (org-export-get-tags headline info)))))
 	(concat indentation bullet title tags)))
     (org-export-collect-headlines info n (and local keyword)) "\n")
    "\n"))

lisp/ox-texinfo.el

@@ -914,10 +914,10 @@ holding contextual information."
   (todo _todo-type priority text tags)
   "Default format function for a headline.
 See `org-texinfo-format-headline-function' for details."
-  (concat (when todo (format "@strong{%s} " todo))
-	  (when priority (format "@emph{#%s} " priority))
+  (concat (and todo (format "@strong{%s} " todo))
+	  (and priority (format "@emph{#%s} " priority))
 	  text
-	  (when tags (format " :%s:" (mapconcat 'identity tags ":")))))
+	  (and tags (concat " " (org-make-tag-string tags)))))
 
 ;;;; Inline Src Block
 
@@ -955,7 +955,7 @@ See `org-texinfo-format-inlinetask-function' for details."
 	 (concat (when todo (format "@strong{%s} " todo))
 		 (when priority (format "#%c " priority))
 		 title
-		 (when tags (format ":%s:" (mapconcat #'identity tags ":"))))))
+		 (when tags (org-make-tag-string tags)))))
     (format "@center %s\n\n%s\n" full-title contents)))
 
 ;;;; Italic