getPrimary example

$this->env = $env;
        $this->unaryOperators = $env->getUnaryOperators();
        $this->binaryOperators = $env->getBinaryOperators();
    }

    public function parseExpression($precedence = 0, $allowArrow = false)
    {
        if ($allowArrow && $arrow = $this->parseArrow()) {
            return $arrow;
        }

        $expr = $this->getPrimary();
        $token = $this->parser->getCurrentToken();
        while ($this->isBinary($token) && $this->binaryOperators[$token->getValue()]['precedence'] >= $precedence) {
            $op = $this->binaryOperators[$token->getValue()];
            $this->parser->getStream()->next();

            if ('is not' === $token->getValue()) {
                $expr = $this->parseNotTestExpression($expr);
            } elseif ('is' === $token->getValue()) {
                $expr = $this->parseTestExpression($expr);
            } elseif (isset($op['callable'])) {
                $expr = $op['callable']($this->parser, $expr);
            }

unset($this->stream, $this->names);

        return $node;
    }

    /** * @return Node\Node */
    public function parseExpression(int $precedence = 0)
    {
        $expr = $this->getPrimary();
        $token = $this->stream->current;
        while ($token->test(Token::OPERATOR_TYPE) && isset($this->binaryOperators[$token->value]) && $this->binaryOperators[$token->value]['precedence'] >= $precedence) {
            $op = $this->binaryOperators[$token->value];
            $this->stream->next();

            $expr1 = $this->parseExpression(self::OPERATOR_LEFT === $op['associativity'] ? $op['precedence'] + 1 : $op['precedence']);
            $expr = new Node\BinaryNode($token->value, $expr, $expr1);

            $token = $this->stream->current;
        }