Module: RubyRich::Markdown::Frontmatter

Defined in:

lib/ruby_rich/markdown.rb

Overview

—- Frontmatter extraction —- Extracts YAML-style frontmatter (delimited by —) and returns [content_without_fm, parsed_pairs, is_vertical].

Constant Summary

VERTICAL_THRESHOLD =

5

Class Method Summary

• .extract(markdown_text) ⇒ Object
• .parse_pairs(block) ⇒ Object
• .unquote(s) ⇒ Object

Class Method Details

.extract(markdown_text) ⇒ Object

# File 'lib/ruby_rich/markdown.rb', line 1207

def self.extract(markdown_text)
  # Strip leading blank lines so that a heredoc like <<~'MD'\n\n---\n
  # is still recognised as having frontmatter.
  stripped = markdown_text.lstrip
  return [markdown_text, nil, false] unless stripped.start_with?("---")

  rest = stripped[3..]
  offset = 3
  rest.each_line do |line|
    trimmed = line.strip
    if trimmed == "---" || trimmed == "..."
      fm_block = stripped[3...offset]
      content = stripped[(offset + line.length)..] || ""
      pairs = parse_pairs(fm_block)
      return [markdown_text, nil, false] if pairs.empty?
      vertical = pairs.length >= VERTICAL_THRESHOLD
      return [content, pairs, vertical]
    end
    offset += line.length
  end
  [markdown_text, nil, false]
end

.parse_pairs(block) ⇒ Object

# File 'lib/ruby_rich/markdown.rb', line 1230

def self.parse_pairs(block)
  pairs = []
  lines = block.lines.map(&:chomp)
  i = 0
  while i < lines.length
    trimmed = lines[i].strip
    i += 1 and next if trimmed.empty? || trimmed.start_with?('#')

    colon_pos = trimmed.index(':')
    i += 1 and next unless colon_pos

    key = trimmed[0...colon_pos].strip
    raw_value = trimmed[(colon_pos + 1)..].strip
    i += 1 and next if key.empty?

    if [">-", ">", "|", "|-"].include?(raw_value)
      # Multiline value with explicit indicator
      i += 1
      parts = []
      while i < lines.length && lines[i].start_with?(' ', "\t")
        part = lines[i].strip
        parts << part unless part.empty?
        i += 1
      end
      pairs << [key, parts.join(" ")]
    elsif raw_value.empty?
      # Empty value: could be a list or an implicit multiline string.
      i += 1
      items = []
      while i < lines.length && lines[i].start_with?(' ', "\t")
        item = lines[i].strip
        items << (item.start_with?("- ") ? item[2..].strip : item)
        i += 1
      end
      pairs << [key, items.empty? ? "" : items.join(", ")]
    else
      pairs << [key, unquote(raw_value)]
      i += 1
    end
  end
  pairs
end

.unquote(s) ⇒ Object

# File 'lib/ruby_rich/markdown.rb', line 1273

def self.unquote(s)
  (s.length >= 2 && ((s.start_with?('"') && s.end_with?('"')) || (s.start_with?("'") && s.end_with?("'")))) ? s[1...-1] : s
end