class RDoc::Markup

RDoc::Markup parses plain text documents and attempts to decompose them into their constituent parts. Some of these parts are high-level: paragraphs, chunks of verbatim text, list entries and the like. Other parts happen at the character level: a piece of bold text, a word in code font. This markup is similar in spirit to that used on WikiWiki webs, where folks create web pages using a simple set of formatting rules.

RDoc::Markup and other markup formats do no output formatting, this is handled by the RDoc::Markup::Formatter subclasses.

Supported Formats

Besides the RDoc::Markup format, the following formats are built in to RDoc:


The markdown format as described by See RDoc::Markdown for details on the parser and supported extensions.


The rdtool format. See RDoc::RD for details on the parser and format.


The TomDoc format as described by See RDoc::TomDoc for details on the parser and supported extensions.

You can choose a markup format using the following methods:

per project

If you build your documentation with rake use RDoc::Task#markup.

If you build your documentation by hand run:

rdoc --markup your_favorite_format --write-options

and commit .rdoc_options and ship it with your packaged gem.

per file

At the top of the file use the :markup: directive to set the default format for the rest of the file.

per comment

Use the :markup: directive at the top of a comment you want to write in a different format.


RDoc::Markup is extensible at runtime: you can add new markup elements to be recognized in the documents that RDoc::Markup parses.

RDoc::Markup is intended to be the basis for a family of tools which share the common requirement that simple, plain-text should be rendered in a variety of different output formats and media. It is envisaged that RDoc::Markup could be the basis for formatting RDoc style comment blocks, Wiki entries, and online FAQs.


This code converts input_string to HTML. The conversion takes place in the convert method, so you can use the same RDoc::Markup converter to convert multiple input strings.

require 'rdoc'

h =

puts h.convert(input_string)

You can extend the RDoc::Markup parser to recognize new markup sequences, and to add regexp handling. Here we make WikiWords significant to the parser, and also make the sequences {word} and <no>text…</no> signify strike-through text. We then subclass the HTML output class to deal with these:

require 'rdoc'

class WikiHtml < RDoc::Markup::ToHtml
  def handle_regexp_WIKIWORD(target)
    "<font color=red>" + target.text + "</font>"

markup =
markup.add_word_pair("{", "}", :STRIKE)
markup.add_html("no", :STRIKE)

markup.add_regexp_handling(/\b([A-Z][a-z]+[A-Z]\w+)/, :WIKIWORD)

wh =, markup
wh.add_tag(:STRIKE, "<strike>", "</strike>")

puts "<body>#{wh.convert}</body>"


Where Encoding support is available, RDoc will automatically convert all documents to the same output encoding. The output encoding can be set via RDoc::Options#encoding and defaults to Encoding.default_external.

RDoc Markup Reference

See RDoc::MarkupReference.



An AttributeManager which handles inline markup.

Public Class Methods

new(attribute_manager = nil) click to toggle source

Take a block of text and use various heuristics to determine its structure (paragraphs, lists, and so on). Invoke an event handler as we identify significant chunks.

# File lib/rdoc/markup.rb, line 146
def initialize attribute_manager = nil
  @attribute_manager = attribute_manager ||
  @output = nil
parse(str) click to toggle source

Parses str into an RDoc::Markup::Document.

# File lib/rdoc/markup.rb, line 116
  def self.parse str
    RDoc::Markup::Parser.parse str
  rescue RDoc::Markup::Parser::Error => e
    $stderr.puts <<-EOF
While parsing markup, RDoc encountered a #{e.class}:

\tfrom #{e.backtrace.join "\n\tfrom "}




Please file a bug report with the above information at:


Public Instance Methods

add_html(tag, name) click to toggle source

Add to the sequences recognized as general markup.

# File lib/rdoc/markup.rb, line 163
def add_html(tag, name)
  @attribute_manager.add_html(tag, name)
add_regexp_handling(pattern, name) click to toggle source

Add to other inline sequences. For example, we could add WikiWords using something like:

parser.add_regexp_handling(/\b([A-Z][a-z]+[A-Z]\w+)/, :WIKIWORD)

Each wiki word will be presented to the output formatter.

# File lib/rdoc/markup.rb, line 175
def add_regexp_handling(pattern, name)
  @attribute_manager.add_regexp_handling(pattern, name)
add_word_pair(start, stop, name) click to toggle source

Add to the sequences used to add formatting to an individual word (such as bold). Matching entries will generate attributes that the output formatters can recognize by their name.

# File lib/rdoc/markup.rb, line 156
def add_word_pair(start, stop, name)
  @attribute_manager.add_word_pair(start, stop, name)
convert(input, formatter) click to toggle source

We take input, parse it if necessary, then invoke the output formatter using a Visitor to render the result.

# File lib/rdoc/markup.rb, line 183
def convert input, formatter
  document = case input
             when RDoc::Markup::Document then
               RDoc::Markup::Parser.parse input

  document.accept formatter