/**
* This only matches constant *strings* (things in quotes or marked for
* translation). Numbers are treated as variables for implementation reasons (so that
* they retain their type when passed to filters).
*
* @static
* @return string
*/
public static function getReFilter()
{
if (self::$_re_filter === null) {
$strdq = '"[^"\\\\]*(?:\\\\.[^"\\\\]*)*"';
// double-quoted string
$strsq = "\\'[^\\'\\\\]*(?:\\\\.[^\\'\\\\]*)*\\'";
// single-quoted string
$i18n_open = '_\\(';
$i18n_close = '\\)';
$constant_string = '(?:' . $i18n_open . $strdq . $i18n_close . '|' . $i18n_open . $strsq . $i18n_close . '|' . $strdq . '|' . $strsq . ')';
$num = '[-+\\.]?\\d[\\d\\.e]*';
$var_chars = '\\w\\.';
$filter_sep = preg_quote(self::FILTER_SEPARATOR);
$arg_sep = preg_quote(self::FILTER_ARGUMENT_SEPARATOR);
self::$_re_filter = '~^(?P<constant>' . $constant_string . ')|^(?P<var>[' . $var_chars . ']+|' . $num . ')|(?:' . $filter_sep . '(?P<filter_name>\\w+)(?:' . $arg_sep . '(?:(?P<constant_arg>' . $constant_string . ')|(?P<var_arg>[' . $var_chars . ']+|' . $num . ')))?)~';
}
return self::$_re_filter;
}
