ox-ascii: Fix descriptive lists

* lisp/ox-ascii.el (org-ascii-quote-margin): Update docstring.
(org-ascii--current-text-width): Properly handle width of text within
nested plain-list items.
(org-ascii-item): Always start a new line for description contents.
Indent them by `org-ascii-quote-margin' characters.

lisp/ox-ascii.el

@@ -177,7 +177,8 @@ Inner margin is applied between each headline."
 
 (defcustom org-ascii-quote-margin 6
   "Width of margin used for quoting text, in characters.
-This margin is applied on both sides of the text."
+This margin is applied on both sides of the text.  It is also
+applied on the left side of contents in descriptive lists."
   :group 'org-export-ascii
   :version "24.4"
   :package-version '(Org . "8.0")
@@ -597,33 +598,23 @@ INFO is a plist used as a communication channel."
                                  'item))))
                  genealogy)
                 (plist-get info :ascii-list-margin))
-	     ;; Text width within a plain-list is restricted by
+             ;; Compute indentation offset due to current list.  It is
-	     ;; indentation of current item.  If that's the case,
+	     ;; `org-ascii-quote-margin' per descriptive item in the
-	     ;; compute it with the help of `:structure' property from
+	     ;; genealogy, bullet's length otherwise.
-	     ;; parent item, if any.
+             (let ((indentation 0))
-	     (let ((item
+               (dolist (e genealogy)
-		    (if (eq (org-element-type element) 'item) element
+                 (cond
-		      (cl-find-if (lambda (parent)
+                  ((not (eq 'item (org-element-type e))))
-				    (eq (org-element-type parent) 'item))
+                  ((eq (org-element-property :type (org-export-get-parent e))
-				  genealogy))))
+                       'descriptive)
-	       (if (not item) 0
+                   (cl-incf indentation org-ascii-quote-margin))
-		 ;; Compute indentation offset of the current item,
+                  (t
-		 ;; that is the sum of the difference between its
+                   (cl-incf indentation
-		 ;; indentation and the indentation of the top item in
+                            (+ (string-width
-		 ;; the list and current item bullet's length.  Also
+                                (or (org-ascii--checkbox e info) ""))
-		 ;; remove checkbox length, and tag length (for
-		 ;; description lists) or bullet length.
-		 (let ((struct (org-element-property :structure item))
-		       (beg-item (org-element-property :begin item)))
-		   (+ (- (org-list-get-ind beg-item struct)
-			 (org-list-get-ind
-			  (org-list-get-top-point struct) struct))
-		      (string-width (or (org-ascii--checkbox item info)
-					""))
                                (string-width
-		       (let ((tag (org-element-property :tag item)))
+                                (org-element-property :bullet e)))))))
-			 (if tag (org-export-data tag info)
+               indentation)))))))
-			   (org-element-property :bullet item))))))))))))))
 
 (defun org-ascii--current-justification (element)
   "Return expected justification for ELEMENT's contents.
@@ -1458,17 +1449,17 @@ contextual information."
 	 (bullet
 	  ;; First parent of ITEM is always the plain-list.  Get
 	  ;; `:type' property from it.
-	  (org-list-bullet-string
 	  (pcase list-type
 	    (`descriptive
 	     (concat checkbox
-		      (org-export-data (org-element-property :tag item) info)
+		     (org-export-data (org-element-property :tag item)
-		      ": "))
+				      info)))
 	    (`ordered
 	     ;; Return correct number for ITEM, paying attention to
 	     ;; counters.
 	     (let* ((struct (org-element-property :structure item))
-		     (bul (org-element-property :bullet item))
+		    (bul (org-list-bullet-string
+			  (org-element-property :bullet item)))
 		    (num (number-to-string
 			  (car (last (org-list-get-item-number
 				      (org-element-property :begin item)
@@ -1476,22 +1467,27 @@ contextual information."
 				      (org-list-prevs-alist struct)
 				      (org-list-parents-alist struct)))))))
 	       (replace-regexp-in-string "[0-9]+" num bul)))
-	     (_ (let ((bul (org-element-property :bullet item)))
+	    (_ (let ((bul (org-list-bullet-string
+			   (org-element-property :bullet item))))
 		 ;; Change bullets into more visible form if UTF-8 is active.
 		 (if (not utf8p) bul
 		   (replace-regexp-in-string
 		    "-" "•"
 		    (replace-regexp-in-string
 		     "+" "⁃"
-		      (replace-regexp-in-string "*" "‣" bul))))))))))
+		     (replace-regexp-in-string "*" "‣" bul))))))))
+	 (indentation (if (eq list-type 'descriptive) org-ascii-quote-margin
+			(string-width bullet))))
     (concat
      bullet
-     (unless (eq list-type 'descriptive) checkbox)
+     checkbox
      ;; Contents: Pay attention to indentation.  Note: check-boxes are
      ;; already taken care of at the paragraph level so they don't
      ;; interfere with indentation.
-     (let ((contents (org-ascii--indent-string contents (string-width bullet))))
+     (let ((contents (org-ascii--indent-string contents indentation)))
-       (if (eq (org-element-type (car (org-element-contents item))) 'paragraph)
+       (if (and (eq (org-element-type (car (org-element-contents item)))
+		    'paragraph)
+		(not (eq list-type 'descriptive)))
 	   (org-trim contents)
 	 (concat "\n" contents))))))