/**
* Merges several regular expressions into one, using the indicated 'glue'.
*
* This function takes care of individual modifiers so it's safe to use
* <i>different</i> modifiers on the individual expressions. The order of
* sub-matches is preserved as well. Numbered back-references are adapted to
* the new overall sub-match count. This means that it's safe to use numbered
* back-refences in the individual expressions!
* If {@link $names} is given, the individual expressions are captured in
* named sub-matches using the contents of that array as names.
* Matching pair-delimiters (e.g. <var>"{…}"</var>) are currently
* <b>not</b> supported.
*
* The function assumes that all regular expressions are well-formed.
* Behaviour is undefined if they aren't.
*
* This function was created after a
* {@link http://stackoverflow.com/questions/244959/ StackOverflow discussion}.
* Much of it was written or thought of by “porneL” and “eyelidlessness”. Many
* thanks to both of them.
*
* @param string $glue A string to insert between the individual expressions.
* This should usually be either the empty string, indicating
* concatenation, or the pipe (<var>"|"</var>), indicating alternation.
* Notice that this string might have to be escaped since it is treated
* as a normal character in a regular expression (i.e. <var>"/"</var> will
* end the expression and result in an invalid output).
* @param array $expressions The expressions to merge. The expressions may
* have arbitrary different delimiters and modifiers.
* @param array $names Optional. This is either an empty array or an array of
* strings of the same length as {@link $expressions}. In that case,
* the strings of this array are used to create named sub-matches for the
* expressions.
* @return string An string representing a regular expression equivalent to the
* merged expressions. Returns <var>FALSE</var> if an error occurred.
*/
function preg_merge($glue, array $expressions, array $names = array())
{
// … then, a miracle occurs.
// Sanity check …
$use_names = ($names !== null and count($names) !== 0);
if ($use_names and count($names) !== count($expressions) or !is_string($glue)) {
return false;
}
$result = array();
// For keeping track of the names for sub-matches.
$names_count = 0;
// For keeping track of *all* captures to re-adjust backreferences.
$capture_count = 0;
foreach ($expressions as $expression) {
if ($use_names) {
$name = str_replace(' ', '_', $names[$names_count++]);
}
// Get delimiters and modifiers:
$stripped = preg_strip($expression);
if ($stripped === false) {
return false;
}
list($sub_expr, $modifiers) = $stripped;
// Re-adjust backreferences:
// We assume that the expression is correct and therefore don't check
// for matching parentheses.
$number_of_captures = preg_match_all('/\\([^?]|\\(\\?[^:]/', $sub_expr, $_);
if ($number_of_captures === false) {
return false;
}
if ($number_of_captures > 0) {
// NB: This looks NP-hard. Consider replacing.
$backref_expr = '/
( # Only match when not escaped:
[^\\\\] # guarantee an even number of backslashes
(\\\\*?)\\2 # (twice n, preceded by something else).
)
\\\\ (\\d) # Backslash followed by a digit.
/x';
$sub_expr = preg_replace_callback($backref_expr, create_function('$m', 'return $m[1] . "\\\\" . ((int)$m[3] + ' . $capture_count . ');'), $sub_expr);
$capture_count += $number_of_captures;
}
// Last, construct the new sub-match:
$modifiers = implode('', $modifiers);
$sub_modifiers = "(?{$modifiers})";
if ($sub_modifiers === '(?)') {
$sub_modifiers = '';
}
$sub_name = $use_names ? "?<{$name}>" : '?:';
$new_expr = "({$sub_name}{$sub_modifiers}{$sub_expr})";
$result[] = $new_expr;
}
return '/' . implode($glue, $result) . '/';
}
/**
* Merges several regular expressions into one, using the indicated 'glue'.
*
* This function takes care of individual modifiers so it's safe to use
* <i>different</i> modifiers on the individual expressions. The order of
* sub-matches is preserved as well. Numbered back-references are adapted to
* the new overall sub-match count. This means that it's safe to use numbered
* back-refences in the individual expressions!
* If {@link $names} is given, the individual expressions are captured in
* named sub-matches using the contents of that array as names.
* Matching pair-delimiters (e.g. <var>"{…}"</var>) are currently
* <b>not</b> supported.
*
* The function assumes that all regular expressions are well-formed.
* Behaviour is undefined if they aren't.
*
* This function was created after a
* {@link http://stackoverflow.com/questions/244959/ StackOverflow discussion}.
* Much of it was written or thought of by “porneL” and “eyelidlessness”. Many
* thanks to both of them.
*
* @param string $glue A string to insert between the individual expressions.
* This should usually be either the empty string, indicating
* concatenation, or the pipe (<var>"|"</var>), indicating alternation.
* Notice that this string might have to be escaped since it is treated
* as a normal character in a regular expression (i.e. <var>"/"</var> will
* end the expression and result in an invalid output).
* @param array $expressions The expressions to merge. The expressions may
* have arbitrary different delimiters and modifiers.
* @param array $names Optional. This is either an empty array or an array of
* strings of the same length as {@link $expressions}. In that case,
* the strings of this array are used to create named sub-matches for the
* expressions.
* @return string An string representing a regular expression equivalent to the
* merged expressions. Returns <var>FALSE</var> if an error occurred.
*/
function preg_merge($glue, array $expressions, array $names = array())
{
// … then, a miracle occurs.
// Sanity check …
$use_names = ($names !== null and count($names) !== 0);
if ($use_names and count($names) !== count($expressions) or !is_string($glue)) {
return false;
}
$result = array();
// For keeping track of the names for sub-matches.
$names_count = 0;
// For keeping track of *all* captures to re-adjust backreferences.
$capture_count = 0;
foreach ($expressions as $expression) {
if ($use_names) {
$name = str_replace(' ', '_', $names[$names_count++]);
}
// Get delimiters and modifiers:
$stripped = preg_strip($expression);
if ($stripped === false) {
return false;
}
list($sub_expr, $modifiers) = $stripped;
// Re-adjust backreferences:
// TODO What about \R backreferences (\0 isn't allowed, though)?
// We assume that the expression is correct and therefore don't check
// for matching parentheses.
$number_of_captures = preg_match_all('/\\([^?]|\\(\\?[^:]/', $sub_expr, $_);
if ($number_of_captures === false) {
return false;
}
if ($number_of_captures > 0) {
$backref_expr = '/
(?<!\\\\) # Not preceded by a backslash,
((?:\\\\\\\\)*?) # zero or more escaped backslashes,
\\\\ (\\d+) # followed by backslash plus digits.
/x';
$sub_expr = preg_replace_callback($backref_expr, create_function('$m', 'return $m[1] . "\\\\" . ((int)$m[2] + ' . $capture_count . ');'), $sub_expr);
$capture_count += $number_of_captures;
}
// Last, construct the new sub-match:
$modifiers = implode('', $modifiers);
$sub_modifiers = "(?{$modifiers})";
if ($sub_modifiers === '(?)') {
$sub_modifiers = '';
}
$sub_name = $use_names ? "?<{$name}>" : '?:';
$new_expr = "({$sub_name}{$sub_modifiers}{$sub_expr})";
$result[] = $new_expr;
}
return '/' . implode($glue, $result) . '/';
}
public function __construct()
{
$this->setInfo(array(parent::NAME => 'CSS', parent::VERSION => '0.8', parent::AUTHOR => array(parent::NAME => 'Konrad Rudolph', parent::WEBSITE => 'madrat.net', parent::EMAIL => '*****@*****.**')));
$this->setExtensions(array('css'));
// The following does not conform to the specs but it is necessary
// else numbers wouldn't be recognized any more.
$nmstart = '-?[a-z]';
$nmchar = '[a-z0-9-]';
$hex = '[0-9a-f]';
list($string, $strmod) = preg_strip(Rule::STRING);
$strmod = implode('', $strmod);
$this->addStates(array('init' => array('comment', 'uri', 'meta', 'id', 'class', 'pseudoclass', 'element', 'block', 'constraint', 'string'), 'block' => array('comment', 'attribute', 'value'), 'constraint' => array('identifier', 'string'), 'value' => array('comment', 'string', 'color', 'number', 'uri', 'identifier', 'important')));
$this->addRules(array('attribute' => "/{$nmstart}{$nmchar}*/i", 'value' => new Rule('/:/', '/;|(?=\\})/'), 'comment' => Rule::C_MULTILINECOMMENT, 'meta' => "/@{$nmstart}{$nmchar}*/i", 'id' => "/#{$nmstart}{$nmchar}*/i", 'class' => "/\\.{$nmstart}{$nmchar}*/", 'pseudoclass' => "/(?<!:):{$nmstart}{$nmchar}*/", 'element' => "/{$nmstart}{$nmchar}*/i", 'block' => new Rule('/\\{/', '/\\}/'), 'constraint' => new Rule('/\\[/', '/\\]/'), 'number' => '/[+-]?(?:\\d+(\\.\\d+)?|\\d*\\.\\d+)(%|em|ex|px|pt|in|cm|mm|pc|deg|g?rad|m?s|k?Hz)?/', 'uri' => "/url\\(\\s*(?:{$string}|[^\\)]*)\\s*\\)/{$strmod}", 'identifier' => "/{$nmstart}{$nmchar}*/i", 'string' => "/{$string}/{$strmod}", 'color' => "/#{$hex}{3}(?:{$hex}{3})?/i", 'important' => '/!\\s*important/'));
$this->addMappings(array('element' => 'keyword', 'id' => 'keyword type', 'class' => 'keyword builtin', 'pseudoclass' => 'preprocessor', 'block' => '', 'constraint' => '', 'value' => '', 'color' => 'string', 'uri' => 'char', 'meta' => 'keyword'));
}
