This expression isolates a string or many strings of any caracthers that are preceded and are followed by a pair of colons in a long text string.
Practical for tooltip insertion. Find a word in the string, search in the database, construct the tooltip and insert within the returned string.
Use with :
preg_match() for one unique result.
preg_match_all() to get all found strings
$tooltip = preg_match_all( "/::(*?)::/", $string, $matches, PREG_PATTERN_ORDER );
Replace each match with each found
$new_string = str_replace( $matches[0], $matches[1], $string );