get_shortcode_regex

Source code

function get_shortcode_regex() {

	global $shortcode_tags;

	$tagnames = array_keys($shortcode_tags);

	$tagregexp = join( '|', array_map('preg_quote', $tagnames) );



	// WARNING! Do not change this regex without changing do_shortcode_tag() and strip_shortcode_tag()

	return

		  '\\['                              // Opening bracket

		. '(\\[?)'                           // 1: Optional second opening bracket for escaping shortcodes: [[tag]]

		. "($tagregexp)"                     // 2: Shortcode name

		. '\\b'                              // Word boundary

		. '('                                // 3: Unroll the loop: Inside the opening shortcode tag

		.     '[^\\]\\/]*'                   // Not a closing bracket or forward slash

		.     '(?:'

		.         '\\/(?!\\])'               // A forward slash not followed by a closing bracket

		.         '[^\\]\\/]*'               // Not a closing bracket or forward slash

		.     ')*?'

		. ')'

		. '(?:'

		.     '(\\/)'                        // 4: Self closing tag ...

		.     '\\]'                          // ... and closing bracket

		. '|'

		.     '\\]'                          // Closing bracket

		.     '(?:'

		.         '('                        // 5: Unroll the loop: Optionally, anything between the opening and closing shortcode tags

		.             '[^\\[]*+'             // Not an opening bracket

		.             '(?:'

		.                 '\\[(?!\\/\\2\\])' // An opening bracket not followed by the closing shortcode tag

		.                 '[^\\[]*+'         // Not an opening bracket

		.             ')*+'

		.         ')'

		.         '\\[\\/\\2\\]'             // Closing shortcode tag

		.     ')?'

		. ')'

		. '(\\]?)';                          // 6: Optional second closing brocket for escaping shortcodes: [[tag]]

}