Fixed Python-Markdown#78. Added support for two line link refs.

Also refactored the reference preprocessor to make this a little easier to
implement. Regex does more now.

markdown/preprocessors.py

@@ -257,25 +257,26 @@ def run(self, lines):
 class ReferencePreprocessor(Preprocessor):
     """ Remove reference definitions from text and store for later use. """
 
-    RE = re.compile(r'^(\ ?\ ?\ ?)\[([^\]]*)\]:\s*([^ ]*)(.*)$', re.DOTALL)
+    TITLE = r'[ ]*(\"(.*)\"|\'(.*)\'|\((.*)\))[ ]*'
+    RE = re.compile(r'^[ ]{0,3}\[([^\]]*)\]:\s*([^ ]*)[ ]*(%s)?$' % TITLE, re.DOTALL)
+    TITLE_RE = re.compile(r'^%s$' % TITLE)
 
     def run (self, lines):
         new_text = [];
-        for line in lines:
+        while lines:
+            line = lines.pop(0)
             m = self.RE.match(line)
             if m:
-                id = m.group(2).strip().lower()
-                link = m.group(3).lstrip('<').rstrip('>')
-                t = m.group(4).strip()  # potential title
+                id = m.group(1).strip().lower()
+                link = m.group(2).lstrip('<').rstrip('>')
+                t = m.group(5) or m.group(6) or m.group(7)
                 if not t:
-                    self.markdown.references[id] = (link, t)
-                elif (len(t) >= 2
-                      and (t[0] == t[-1] == "\""
-                           or t[0] == t[-1] == "\'"
-                           or (t[0] == "(" and t[-1] == ")") ) ):
-                    self.markdown.references[id] = (link, t[1:-1])
-                else:
-                    new_text.append(line)
+                    # Check next line for title
+                    tm = self.TITLE_RE.match(lines[0])
+                    if tm:
+                        lines.pop(0)
+                        t = tm.group(2) or tm.group(3) or tm.group(4)
+                self.markdown.references[id] = (link, t)
             else:
                 new_text.append(line)
 

tests/basic/links-reference.html

@@ -18,4 +18,5 @@
 breaks[] with two spaces.</p>
 <p><a href="http://example.com" title="No more hanging empty bracket!">short ref</a></p>
 <p><a href="http://example.com" title="No more hanging empty bracket!">short 
-ref</a></p>
+ref</a></p>
+<p><a href="http://example.com" title="Title on next line.">a ref</a></p>

tests/basic/links-reference.txt

@@ -54,3 +54,8 @@ breaks[] with two spaces.
 ref]
 
 [short ref]: http://example.com "No more hanging empty bracket!"
+
+[a ref]
+
+[a ref]: http://example.com
+    "Title on next line."