Fix beginning and end of defun functions

This should fix GH-197.

markdown-mode.el

@@ -6044,29 +6044,58 @@ a list."
 
 (defun markdown-beginning-of-defun (&optional arg)
   "`beginning-of-defun-function' for Markdown.
-Move backward to the beginning of the current or previous section.
-When ARG is non-nil, repeat that many times.  When ARG is negative,
-move forward to the ARG-th following section."
-  (interactive "P")
-  (or arg (setq arg 1))
-  (forward-char 1)
-  (or (re-search-backward markdown-regex-header nil t arg)
-      (goto-char (point-min))))
-
-(defun markdown-end-of-defun (&optional arg)
-  "`end-of-defun-function' for Markdown.
-Move forward to the end of the current or following section.
-When ARG is non-nil, repeat that many times.  When ARG is negative,
-move back to the ARG-th preceding section."
-  (interactive "P")
+This is used to find the beginning of the defun and should behave
+like ‘beginning-of-defun’, returning non-nil if it found the
+beginning of a defun.  It moves the point backward, right before a
+heading which defines a defun.  When ARG is non-nil, repeat that
+many times.  When ARG is negative, move forward to the ARG-th
+following section."
   (or arg (setq arg 1))
-  (when (looking-at markdown-regex-header)
-    (goto-char (match-beginning 0))
-    (forward-char 1))
-  (if (re-search-forward markdown-regex-header nil t arg)
-      (goto-char (match-beginning 0))
-    (goto-char (point-max)))
-  (skip-syntax-backward "-"))
+  (when (< arg 0) (end-of-line))
+  ;; Adjust position for setext headings.
+  (when (and (thing-at-point-looking-at markdown-regex-header-setext)
+             (not (= (point) (match-beginning 0)))
+             (not (markdown-code-block-at-point-p)))
+    (goto-char (match-end 0)))
+  (let (found)
+    ;; Move backward with positive argument.
+    (while (and (not (bobp)) (> arg 0))
+      (setq found nil)
+      (while (and (not found)
+                  (not (bobp))
+                  (re-search-backward markdown-regex-header nil 'move))
+        (when (not (markdown-code-block-at-pos (match-beginning 0))))
+        (setq found (match-beginning 0)))
+      (setq arg (1- arg)))
+    ;; Move forward with negative argument.
+    (while (and (not (eobp)) (< arg 0))
+      (setq found nil)
+      (while (and (not found)
+                  (not (eobp))
+                  (re-search-forward markdown-regex-header nil 'move))
+        (when (not (markdown-code-block-at-pos (match-beginning 0))))
+        (setq found (match-beginning 0)))
+      (setq arg (1+ arg)))
+    (when found
+      (beginning-of-line)
+      t)))
+
+(defun markdown-end-of-defun ()
+  "`end-of-defun-function’ for Markdown.
+This is used to find the end of the defun at point.
+It is called with no argument, right after calling ‘beginning-of-defun-raw’,
+so it can assume that point is at the beginning of the defun body.
+It should move point to the first position after the defun."
+  (or (eobp) (forward-char 1))
+  (let (found)
+    (while (and (not found)
+                (not (eobp))
+                (re-search-forward markdown-regex-header nil 'move))
+      (when (not (markdown-code-block-at-pos (match-beginning 0)))
+        (setq found (match-beginning 0))))
+    (when found
+      (goto-char found)
+      (skip-syntax-backward "-"))))
 
 (make-obsolete 'markdown-beginning-of-block 'markdown-beginning-of-text-block "v2.2")