parse link references as blocks to improve performance

Parsedown.php

@@ -75,18 +75,6 @@ class Parsedown
 			}
 		}
 		
-		# Extracts link references.
-		
-		if (preg_match_all('/^[ ]{0,3}\[(.+)\][ ]?:[ ]*\n?[ ]*(.+)$/m', $text, $matches, PREG_SET_ORDER))
-		{
-			foreach ($matches as $matches)
-			{
-				$this->reference_map[strtolower($matches[1])] = $matches[2];
-				
-				$text = str_replace($matches[0], '', $text);
-			}
-		}
-		
 		# ~ 
 		
 		$text = preg_replace('/\n\s*\n/', "\n\n", $text);
@@ -217,7 +205,7 @@ class Parsedown
 			
 			# Quick Paragraph 
 			
-			if ($line[0] >= 'A' and $line[0] !== '_')
+			if ($line[0] >= 'A' and $line[0] !== '_' and $line[0] !== '[')
 			{
 				goto paragraph; # trust me 
 			}
@@ -282,10 +270,22 @@ class Parsedown
 				continue;
 			}
 			
-			# ~  
+			# ~ 
 			
 			$pure_line = ltrim($line);
 			
+			# Link Reference 
+			
+			if ($pure_line[0] === '[' and preg_match('/^\[(.+?)\]:[ ]*([^ ]+)/', $pure_line, $matches))
+			{
+				$label = $matches[1];
+				$url = trim($matches[2], '<>');
+				
+				$this->reference_map[$label] = $url;
+				
+				continue;
+			}
+			
 			# Blockquote 
 			
 			if ($pure_line[0] === '>' and preg_match('/^>[ ]?(.*)/', $pure_line, $matches))

tests/data/reference_link.html

 <p>Here's a <a href="http://parsedown.org">reference link</a>.</p>
-<p>Here's <a href="http://parsedown.org">one</a> with an alternative syntax.</p>
 <p>Here's <a href="http://parsedown.org">one</a> on the next line.</p>
-<p>Here's <a href="http://parsedown.org">one</a> on 2 lines.</p>
 <p>Here's <a href="http://parsedown.org/tests/">one</a> with a different URL.</p>
 <p>Here's <a href="http://parsedown.org">one</a> with a semantic name.</p>
 <p>Here's <a href="http://parsedown.org">one</a> with definition name on the next line.</p>
 <p>Here's [one][404] with no definition.</p>
 <p>Here's an image: <img alt="Markdown Logo" src="/md.png"></p>
 <p>Here's an <a href="http://google.com">implicit one</a>.</p>
-<p>Here's an <a href="http://google.com">implicit one</a>.</p>
 <p>Here's an <a href="http://google.com">implicit one</a> with an empty link definition.</p>
 <p>Here's a <a href="http://parsedown.org">multiline
 one</a> defined on 2 lines.</p>
\ No newline at end of file

tests/data/reference_link.md

@@ -2,21 +2,12 @@ Here's a [reference link][1].
 
 [1]: http://parsedown.org
 
-Here's [one] [2] with an alternative syntax.
+Here's [one][2] on the next line.
+[2]: http://parsedown.org
 
-[2] :http://parsedown.org
+Here's [one][3] with a different URL.
 
-Here's [one][3] on the next line.
-[3]: http://parsedown.org
-
-Here's [one][4] on 2 lines.
-
-[4]:
-http://parsedown.org
-
-Here's [one][5] with a different URL.
-
-[5]: http://parsedown.org/tests/
+[3]: http://parsedown.org/tests/
 
 Here's [one][website] with a semantic name.
 
@@ -33,8 +24,6 @@ Here's an image: ![Markdown Logo][image]
 
 Here's an [implicit one].
 
-Here's an [implicit one].
-
 [implicit one]: http://google.com
 
 Here's an [implicit one][] with an empty link definition.