protected function generateDigit(
        ?NodeInterface $parent,
        ?string $name
    ): NodeInterface{
        return new DigitNode($this, $parent, $name);
    }
protected function generateDigit(
        ?NodeInterface $parent,
        ?string $name
    ): NodeInterface{
        return new DigitNode($this, $parent, $name);
    }
protected function generateDigit ( ? NodeInterface $ parent , ? string $ name ) : NodeInterface { return new DigitNode ( $ this , $ parent , $ name ) ; }
Generate digit node.

@param NodeInterface|null $parent
@param string|null        $name

@return NodeInterface
Generate digit node .