Flow\Parser::parseMacro PHP Method

    protected function parseMacro($token)
    {
        if (!empty($this->currentBlock)) {
            throw new SyntaxError('cannot declare macros inside blocks', $token);
        }
        if ($this->inMacro) {
            throw new SyntaxError('cannot declare macros inside another macro', $token);
        }
        $this->inMacro = true;
        $name = $this->parseName()->getValue();
        if (isset($this->macros[$name])) {
            throw new SyntaxError(sprintf('macro "%s" already defined', $name), $token);
        }
        $args = array();
        if ($this->stream->consume(Token::OPERATOR, '(')) {
            while (!$this->stream->test(Token::OPERATOR, ')')) {
                if (!empty($args)) {
                    $this->stream->expect(Token::OPERATOR, ',');
                    if ($this->stream->test(Token::OPERATOR, ')')) {
                        break;
                    }
                }
                $key = $this->parseName()->getValue();
                if ($this->stream->consume(Token::OPERATOR, '=')) {
                    $val = $this->parseLiteralExpression();
                } else {
                    $val = new Expression\ConstantExpression(null, $token->getLine());
                }
                $args[$key] = $val;
            }
            $this->stream->expect(Token::OPERATOR, ')');
        }
        $this->stream->expect(Token::BLOCK_END);
        $body = $this->subparse('endmacro');
        if ($this->stream->next()->getValue() != 'endmacro') {
            throw new SyntaxError('malformed macro statement', $token);
        }
        $this->stream->consume(Token::NAME, $name);
        $this->stream->expect(Token::BLOCK_END);
        $this->macros[$name] = new Node\MacroNode($name, $args, $body, $token->getLine());
        $this->inMacro = false;
    }