check() check() : boolean|string Checks if the rule parameters are valid. Returns boolean|string — True if this rule is valid, an error message otherwise.
requires() requires() : array Returns a list of sieve extensions required for this rule and any sub-rules. Returns array — A Sieve extension list.
__construct() __construct(array $vars = array()) Constructor. Parameters array $vars Any required parameters.
generate() generate() : string Returns a script snippet representing this rule and any sub-rules. Returns string — A Sieve script snippet.