Update filter_var_url function.

Limonade no longer requires the filter extension (http://www.php.net/manual/en/book.filter.php),  so it will improve compatibility with older PHP versions.
Note that the regexp is quite permissive and might be improved

lib/limonade.php

@@ -2504,23 +2504,21 @@ function array_replace( array &$array, array &$array1 )
   }
 }
 
-if(PHP_VERSION == '5.2.13' || PHP_VERSION == '5.3.2')
-{
-  # There is a bug with filter_var($site_url , FILTER_VALIDATE_URL); 
-  # http://www.mail-archive.com/php-bugs@lists.php.net/msg134778.html
-  function filter_var_url($str)
-  {
-    $regexp = '@^http(s)?://[-[:alnum:]]+\.[-[:alnum:]]+\.[a-zA-Z]{2,4}(:[0-9]+)?(.*)?$@';
-    $options = array( "options" => array("regexp" => $regexp ));
-    return filter_var($str, FILTER_VALIDATE_REGEXP, $options);
-  }
-}
-else
+/**
+ * Check if a string is an url
+ *
+ * This implementation no longer requires 
+ * {@link http://www.php.net/manual/en/book.filter.php the filter extenstion}, 
+ * so it will improve compatibility with older PHP versions.
+ *
+ * @param string $str 
+ * @return false, str   the string if true, false instead
+ */
+function filter_var_url($str)
 {
-  function filter_var_url($str)
-  {
-    return filter_var($str, FILTER_VALIDATE_URL);
-  }
+  $regexp = '@^https?://([-[:alnum:]]+\.)+[a-zA-Z]{2,6}(:[0-9]+)?(.*)?$@';
+  $options = array( "options" => array("regexp" => $regexp ));
+  return preg_match($regexp, $str) ? $str : false;
 }
 
 

tests/main.php

@@ -186,8 +186,14 @@ function test_main_url_for()
      assert_equal(url_for('one', '', 'three'), '/one/three');
      assert_equal(url_for('one', null, 'three'), '/one/three');
      assert_equal(url_for('my/hash#test'), '/my/hash#test');
+
      $site_url = 'http://www.limonade-php.net';
      assert_true((bool) filter_var_url($site_url));
+     assert_true((bool) filter_var_url('http://example.com'));
+     assert_true((bool) filter_var_url('http://example.com:2000/'));
+     assert_true((bool) filter_var_url('https://www.example.com:2000'));
+     assert_true((bool) filter_var_url('http://test.example.com/?var1=true&var2=34'));
+     assert_false(filter_var_url('not an url'));
 
      assert_equal(url_for($site_url), $site_url);
      //var_dump(url_for($site_url, 'examples'));