public static function consume()

in src/unparsed-blocks/ListItem.php [49:183]
111 lines of code
21 McCabe index (conditional complexity)

  public static function consume(
    Context $context,
    Lines $lines,
  ): ?(ListItem, Lines) {
    $max_indent = $context->getContext(self::MAX_INDENT_CONTEXT);
    invariant(
      $max_indent is int,
      'expected to get a maximum indentation from context, got a %s',
      \gettype($max_indent),
    );

    // Consume leading whitespace
    list($column, $line, $lines) = $lines->getColumnFirstLineAndRest();
    list($_, $line, $n) = Lines::stripUpToNLeadingWhitespace(
      $line,
      $max_indent,
      $column,
    );
    $matches = Regex\first_match(
      $line,
      re"/^(?<marker>[-+*]|(?<digits>[0-9]{1,9})[.)])/",
    );
    if ($matches is null) {
      return null;
    }

    // Consume marker
    $marker_length = Str\length($matches[0]);
    $indent_cols = $n + $marker_length;
    $column += $indent_cols;
    $line = Str\slice($line, $marker_length);

    // Consume post-marker whitespace
    if (Lines::isBlankLine($line)) {
      $line = null;
      $n = 1;
    } else if (Lines::stripNLeadingWhitespace($line, 5, $column) !== null) {
      // `-     foo` is `<li><pre><code>foo</pre></code></li>`
      list($_, $line, $n) =
        Lines::stripUpToNLeadingWhitespace($line, 1, $column);
    } else {
      list($_, $line, $n) =
        Lines::stripUpToNLeadingWhitespace($line, 4, $column);
    }
    if ($n === 0) {
      return null;
    }

    $indent_cols += $n;
    $column += $n;

    $ordered = ($matches['digits'] ?? '') !== '';
    $number = $ordered ? ((int) $matches['digits']) : null;
    $delimiter = Str\trim_left($matches['marker'], '0123456789');

    $matched = vec[];
    if ($line !== null) {
      $matched[] = tuple($column, $line);
    }
    $pre_blank_line = null;

    while (!$lines->isEmpty()) {
      list($column, $line, $rest) = $lines->getColumnFirstLineAndRest();
      if (Lines::isBlankLine($line)) {
        if (C\is_empty($matched)) {
          break;
        }
        if ($pre_blank_line === null) {
          $pre_blank_line = tuple($matched, $lines);
        }

        $matched[] = tuple($column, $line);
        $lines = $rest;
        continue;
      }

      $indented = Lines::stripNLeadingWhitespace($line, $indent_cols, $column);
      if ($indented !== null) {
        $matched[] = tuple($column + $indent_cols, $indented);
        $pre_blank_line = null;
        $lines = $rest;
        continue;
      }

      $maybe_thematic_break = ThematicBreak::consume($context, $lines);
      if ($maybe_thematic_break !== null) {
        break;
      }

      if ($pre_blank_line !== null) {
        break;
      }

      if (C\is_empty($matched)) {
        break;
      }

      // Laziness - explicitly check for a list item as empty list items are
      // valid paragraph continuation text
      try {
        $context->pushContext(self::MAX_INDENT_CONTEXT, $indent_cols - 1);
        if (ListItem::consume($context, $lines) !== null) {
          break;
        }
      } finally {
        $context->popContext(self::MAX_INDENT_CONTEXT);
      }

      if (!_Private\is_paragraph_continuation_text($context, $lines)) {
        break;
      }

      $matched[] = tuple($column, $line);
      $lines = $rest;
    }

    if (C\is_empty($matched) && $context->isInParagraphContinuation()) {
      return null;
    }

    if ($pre_blank_line !== null) {
      list($matched, $lines) = $pre_blank_line;
    }

    return tuple(
      static::createFromContents(
        $context,
        $indent_cols,
        $delimiter,
        $number,
        new Lines($matched),
      ),
      $lines,
    );
  }