Look through the text at line indentation. We flag each line as being Blank, a paragraph, a list element, or verbatim text

Source Code

# File rdoc/markup/simple_markup.rb, line 272
def assign_types_to_lines(margin = 0, level = 0)

  while line = @lines.next
    if line.isBlank?
      line.stamp(Line::BLANK, level)
      next
    end

    # if a line contains non-blanks before the margin, then it must belong
    # to an outer level

    text = line.text

    for i in 0...margin
      if text[i] != SPACE
        @lines.unget
        return
      end
    end

    active_line = text[margin..-1]

    # Rules (horizontal lines) look like
    #
    #  ---   (three or more hyphens)
    #
    # The more hyphens, the thicker the rule
    #

    if /^(---+)\s*$/ =~ active_line
      line.stamp(Line::RULE, level, $1.length-2)
      next
    end

    # Then look for list entries. First the ones that have to have
    # text following them (* xxx, - xxx, and dd. xxx)

    if SIMPLE_LIST_RE =~ active_line

      offset = margin + $1.length
      prefix = $2
      prefix_length = prefix.length

      flag = case prefix
             when "*","-" then ListBase::BULLET
             when /^\d/   then ListBase::NUMBER
             when /^[A-Z]/ then ListBase::UPPERALPHA
             when /^[a-z]/ then ListBase::LOWERALPHA
             else raise "Invalid List Type: #{self.inspect}"
             end

      line.stamp(Line::LIST, level+1, prefix, flag)
      text[margin, prefix_length] = " " * prefix_length
      assign_types_to_lines(offset, level + 1)
      next
    end


    if LABEL_LIST_RE =~ active_line
      offset = margin + $1.length
      prefix = $2
      prefix_length = prefix.length

      next if handled_labeled_list(line, level, margin, offset, prefix)
    end

    # Headings look like
    # = Main heading
    # == Second level
    # === Third
    #
    # Headings reset the level to 0

    if active_line[0] == ?= and active_line =~ /^(=+)\s*(.*)/
      prefix_length = $1.length
      prefix_length = 6 if prefix_length > 6
      line.stamp(Line::HEADING, 0, prefix_length)
      line.strip_leading(margin + prefix_length)
      next
    end

    # If the character's a space, then we have verbatim text,
    # otherwise 

    if active_line[0] == SPACE
      line.strip_leading(margin) if margin > 0
      line.stamp(Line::VERBATIM, level)
    else
      line.stamp(Line::PARAGRAPH, level)
    end
  end
end