Developer
<?php
declare(strict_types=1);
/*
* This file is part of the league/commonmark package.
*
* (c) Colin O'Dell <colinodell@gmail.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace League\CommonMark\Parser\Block;
use League\CommonMark\Parser\Cursor;
use League\CommonMark\Parser\MarkdownParserStateInterface;
use League\CommonMark\Util\RegexHelper;
/**
* @internal
*
* This "parser" is actually a performance optimization.
*
* Most lines in a typical Markdown document probably won't match a block start. This is especially true for lines starting
* with letters - nothing in the core CommonMark spec or our supported extensions will match those lines as blocks. Therefore,
* if we can identify those lines and skip block start parsing, we can optimize performance by ~10%.
*
* Previously this optimization was hard-coded in the MarkdownParser but did not allow users to override this behavior.
* By implementing this optimization as a block parser instead, users wanting custom blocks starting with letters
* can instead register their block parser with a higher priority to ensure their parser is always called first.
*/
final class SkipLinesStartingWithLettersParser implements BlockStartParserInterface
{
public function tryStart(Cursor $cursor, MarkdownParserStateInterface $parserState): ?BlockStart
{
if (! $cursor->isIndented() && RegexHelper::isLetter($cursor->getNextNonSpaceCharacter())) {
$cursor->advanceToNextNonSpaceOrTab();
return BlockStart::abort();
}
return BlockStart::none();
}
}
Developer
To ensure a smooth integration process and optimal performance, follow these best practices: