@@ 998,22 998,30 @@ Return the list of results."
 	 (link-text (substring (car (cdr splitted)) 0 -2)) ; Omit the ending ]]
 	 (id (car (cdr (assoc custom-id mapping))))
 	 (type (car (cdr (cdr (assoc custom-id mapping))))))
-    ;; I need to know the type to know whether to link to a page or an article.
-    (format "[[file:{filename}/%ss/%s/%s.rst][%s]]"
-	    type
-	    opel-output-dir-name
-	    id
-	    link-text)))
+    (if (null id)
+	;; This is an internal link /within/ a post.
+	matched-text
+      ;; Link to another post.
+      ;; I need to know the type to know whether to link to a page or an article.
+      (format "[[file:{filename}/%ss/%s/%s.rst][%s]]"
+	      type
+	      opel-output-dir-name
+	      id
+	      link-text))))
     
 (defun opel--sub-internal-link-wo-text (matched-text mapping)
   "Convert \[\[#blah]] to the appropriate link for Pelican."
   (let* ((custom-id (substring (car splitted) 2 -2))
 	 (id (car (cdr (assoc custom-id mapping))))
 	 (type (car (cdr (cdr (assoc custom-id mapping))))))
-    (format "[[file:{filename}/%ss/%s/%s.rst]]"
-	    type
-	    opel-output-dir-name
-	    id)))
+    (if (null id)
+	;; This is an internal link /within/ a post.
+	matched-text
+      ;; Link to another post.
+      (format "[[file:{filename}/%ss/%s/%s.rst]]"
+	      type
+	      opel-output-dir-name
+	      id))))
 
     
 (defun opel--fix-internal-links (post-text custom-id mapping)

          

@@ 92,9 92,13 @@ heading as a Pelican post:
 
 Do not nest pelican posts. I have no idea what will happen if you do,
 and I do not plan on catching that scenario.
-*** Linking To Another Post
+*** Links
+**** Linking To Another Post
 If you want a link to another post, assign the post a ~CUSTOM_ID~
 property, and create an [[https://orgmode.org/manual/Internal-Links.html][internal link]].
+**** Linking to a Headline Within a Post
+Just as with links to other posts, assign the node a ~CUSTOM_ID~
+property and create an [[https://orgmode.org/manual/Internal-Links.html][internal link]].
 *** Images
 To insert an image, enter:
 

          
@@ 303,7 307,7 @@ updating it without a backup plan!/
 
 Here are all the function definitions.
 
-#+name: all-definitions
+#+name: opel-all-definitions
 #+BEGIN_SRC elisp :lexical t :tangle opel.el
 <<header>>
 <<license>>

          
@@ 1756,6 1760,12 @@ Return the list of results."
 #+RESULTS: custom-id-mapping
 : opel--construct-customid-mapping
 **** Fix Internal Links
+
+We need to distinguish between links to other posts and links to a
+headline within the current post. Both will be linked to using
+~CUSTOM_ID~. The latter, though, will not be in our mapping, and that's
+how we'll distinguish them.
+
 #+name: sub-internal-link
 #+BEGIN_SRC elisp 
 (defun opel--sub-internal-link-with-text (matched-text mapping)

          
@@ 1775,22 1785,30 @@ Return the list of results."
 	 (link-text (substring (car (cdr splitted)) 0 -2)) ; Omit the ending ]]
 	 (id (car (cdr (assoc custom-id mapping))))
 	 (type (car (cdr (cdr (assoc custom-id mapping))))))
-    ;; I need to know the type to know whether to link to a page or an article.
-    (format "[[file:{filename}/%ss/%s/%s.rst][%s]]"
-	    type
-	    opel-output-dir-name
-	    id
-	    link-text)))
+    (if (null id)
+	;; This is an internal link /within/ a post.
+	matched-text
+      ;; Link to another post.
+      ;; I need to know the type to know whether to link to a page or an article.
+      (format "[[file:{filename}/%ss/%s/%s.rst][%s]]"
+	      type
+	      opel-output-dir-name
+	      id
+	      link-text))))
     
 (defun opel--sub-internal-link-wo-text (matched-text mapping)
   "Convert \[\[#blah]] to the appropriate link for Pelican."
   (let* ((custom-id (substring (car splitted) 2 -2))
 	 (id (car (cdr (assoc custom-id mapping))))
 	 (type (car (cdr (cdr (assoc custom-id mapping))))))
-    (format "[[file:{filename}/%ss/%s/%s.rst]]"
-	    type
-	    opel-output-dir-name
-	    id)))
+    (if (null id)
+	;; This is an internal link /within/ a post.
+	matched-text
+      ;; Link to another post.
+      (format "[[file:{filename}/%ss/%s/%s.rst]]"
+	      type
+	      opel-output-dir-name
+	      id))))
 
     
 #+END_SRC

          
@@ 2083,3 2101,6 @@ The function that does it all.
 		      (buffer-substring (point-min) (point-max)))))
 		    
 #+END_SRC
+
+#+RESULTS: opel-convert-heading-to-post
+: opel-convert-heading-to-post