Symfony\Component\CssSelector\XPath\Extension
FunctionExtension::translateNthChild() public WC 1.0
{} Это метод класса: FunctionExtension{}
Хуков нет.
Возвращает
XPathExpr.
Использование
$FunctionExtension = new FunctionExtension(); $FunctionExtension->translateNthChild( $xpath, $function, $last, $addNameTest );
- $xpath(XPathExpr) (обязательный)
- -
- $function(FunctionNode) (обязательный)
- -
- $last(true/false)
- -
- $addNameTest(true/false)
- -
Код FunctionExtension::translateNthChild() FunctionExtension::translateNthChild WC 5.0.0
public function translateNthChild(XPathExpr $xpath, FunctionNode $function, $last = false, $addNameTest = true)
{
try {
list($a, $b) = Parser::parseSeries($function->getArguments());
} catch (SyntaxErrorException $e) {
throw new ExpressionErrorException(sprintf('Invalid series: %s', implode(', ', $function->getArguments())), 0, $e);
}
$xpath->addStarPrefix();
if ($addNameTest) {
$xpath->addNameTest();
}
if (0 === $a) {
return $xpath->addCondition('position() = '.($last ? 'last() - '.($b - 1) : $b));
}
if ($a < 0) {
if ($b < 1) {
return $xpath->addCondition('false()');
}
$sign = '<=';
} else {
$sign = '>=';
}
$expr = 'position()';
if ($last) {
$expr = 'last() - '.$expr;
--$b;
}
if (0 !== $b) {
$expr .= ' - '.$b;
}
$conditions = array(sprintf('%s %s 0', $expr, $sign));
if (1 !== $a && -1 !== $a) {
$conditions[] = sprintf('(%s) mod %d = 0', $expr, $a);
}
return $xpath->addCondition(implode(' and ', $conditions));
// todo: handle an+b, odd, even
// an+b means every-a, plus b, e.g., 2n+1 means odd
// 0n+b means b
// n+0 means a=1, i.e., all elements
// an means every a elements, i.e., 2n means even
// -n means -1n
// -1n+6 means elements 6 and previous
}