League\CommonMark\Block\Parser\BlockQuoteParser::parse PHP Method

    public function parse(ContextInterface $context, Cursor $cursor)
    {
        if ($cursor->isIndented()) {
            return false;
        }
        if ($cursor->getFirstNonSpaceCharacter() !== '>') {
            return false;
        }
        $cursor->advanceToFirstNonSpace();
        $cursor->advance();
        $cursor->advanceBySpaceOrTab();
        $context->addBlock(new BlockQuote());
        return true;
    }