public function format(DateTimePrintContext $context, &$buf)
{
$length = strlen($buf);
if ($this->optional) {
$context->startOptional();
}
try {
foreach ($this->printerParsers as $pp) {
if ($pp->format($context, $buf) === false) {
$buf = substr($buf, 0, $length);
// reset buffer
return true;
}
}
} finally {
if ($this->optional) {
$context->endOptional();
}
}
return true;
}
