# class RDoc::Markdown

`RDoc::Markdown` as described by the markdown syntax.

To choose `Markdown` as your only default format see Saved Options at `RDoc::Options` for instructions on setting up a `.rdoc_options` file to store your project default.

## Usage¶ ↑

Here is a brief example of using this parse to read a markdown file by hand.

    data = File.read("README.md")
    formatter = RDoc::Markup::ToHtml.new(RDoc::Options.new, nil)
    html = RDoc::Markdown.parse(data).accept(formatter)

    # do something with html

## Extensions¶ ↑

The following markdown extensions are supported by the parser, but not all are used in `RDoc` output by default.

### `RDoc`¶ ↑

The `RDoc` `Markdown` parser has the following built-in behaviors that cannot be disabled.

Underscores embedded in words are never interpreted as emphasis. (While the markdown dingus emphasizes in-word underscores, neither the `Markdown` syntax nor MarkdownTest mention this behavior.)

For HTML output, `RDoc` always auto-links bare URLs.

### Break on Newline¶ ↑

The `break_on_newline` extension converts all newlines into hard line breaks as in Github Flavored Markdown. This extension is disabled by default.

### CSS¶ ↑

The `css` extension enables CSS blocks to be included in the output, but they are not used for any built-in `RDoc` output format. This extension is disabled by default.

Example:

    <style type="text/css">
    h1 { font-size: 3em }
    </style>

### Definition Lists¶ ↑

The `definition_lists` extension allows definition lists using the PHP Markdown Extra syntax, but only one label and definition are supported at this time. This extension is enabled by default.

Example:

    cat
    :   A small furry mammal
    that seems to sleep a lot

    ant
    :   A little insect that is known
    to enjoy picnics

Produces:

cat

  A small furry mammal that seems to sleep a lot

ant

  A little insect that is known to enjoy picnics

### Strike¶ ↑

Example:

    This is ~~striked~~.

Produces:

This is ~striked~.

### Github¶ ↑

The `github` extension enables a partial set of Github Flavored Markdown. This extension is enabled by default.

Supported github extensions include:

#### Fenced code blocks¶ ↑

Use ````` around a block of code instead of indenting it four spaces.

#### Syntax highlighting¶ ↑

Use ```` ruby` as the start of a code fence to add syntax highlighting. (Currently only `ruby` syntax is supported).

### HTML¶ ↑

Enables raw HTML to be included in the output. This extension is enabled by default.

Example:

    <table>
    ...
    </table>

### Notes¶ ↑

The `notes` extension enables footnote support. This extension is enabled by default.

Example:

    Here is some text[^1] including an inline footnote ^[for short footnotes]

    ...

    [^1]: With the footnote text down at the bottom

Produces:

Here is some text1 including an inline footnote 2

## Limitations¶ ↑

- Link titles are not used

- Footnotes are collapsed into a single paragraph

## Author¶ ↑

This markdown parser is a port to kpeg from peg-markdown by John MacFarlane.

It is used under the MIT license:

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

The port to kpeg was performed by Eric Hodel and Evan Phoenix

1 With the footnote text down at the bottom

2 for short footnotes

### Constants

DEFAULT_EXTENSIONS

  Extensions enabled by default

EXTENSIONS

  Supported extensions

### Public Class Methods

new (extensions = DEFAULT_EXTENSIONS, debug = false)
Source

    # File lib/rdoc/markdown.rb, line 668
    def initialize extensions = DEFAULT_EXTENSIONS, debug = false
      @debug      = debug
      @formatter  = RDoc::Markup::ToJoinedParagraph.new
      @extensions = extensions

      @references          = nil
      @unlinked_references = nil

      @footnotes       = nil
      @note_order      = nil
    end

Creates a new markdown parser that enables the given `extensions`.

parse (markdown)
Source

    # File lib/rdoc/markdown.rb, line 656
    def self.parse markdown
      parser = new

      parser.parse markdown
    end

Parses the `markdown` document into an RDoc::Document using the default extensions.

### Public Instance Methods

emphasis (text)
Source

    # File lib/rdoc/markdown.rb, line 683
    def emphasis text
      if text =~ /\A[a-z\d.\/]+\z/i then
        "_#{text}_"
      else
        "<em>#{text}</em>"
      end
    end

Wraps `text` in emphasis for rdoc inline formatting

link_to (content, label = content, text = nil)
Source

    # File lib/rdoc/markdown.rb, line 737
    def link_to content, label = content, text = nil
      raise ParseError, 'enable notes extension' if
        content.start_with? '^' and label.equal? content

      if ref = @references[label] then
        "{#{content}}[#{ref}]"
      elsif label.equal? content then
        "[#{content}]#{text}"
      else
        "[#{content}]#{text}[#{label}]"
      end
    end

Finds a link reference for `label` and creates a new link to it with `content` as the link text. If `label` was not encountered in the reference-gathering parser pass the label and content are reconstructed with the linking `text` (usually whitespace).

list_item_from (unparsed)
Source

    # File lib/rdoc/markdown.rb, line 754
    def list_item_from unparsed
      parsed = inner_parse unparsed.join
      RDoc::Markup::ListItem.new nil, *parsed
    end

Creates an RDoc::Markup::ListItem by parsing the `unparsed` content from the first parsing pass.

note (label)
Source

    # File lib/rdoc/markdown.rb, line 762
    def note label
      #foottext = "rdoc-label:foottext-#{label}:footmark-#{label}"

      #ref.replace foottext if ref = @unlinked_notes.delete(label)

      @notes[label] = foottext

      #"{^1}[rdoc-label:footmark-#{label}:foottext-#{label}] "
    end

Stores `label` as a note and fills in previously unknown note references.

note_for (ref)
Source

    # File lib/rdoc/markdown.rb, line 776
    def note_for ref
      @note_order << ref

      label = @note_order.length

      "{*#{label}}[rdoc-label:foottext-#{label}:footmark-#{label}]"
    end

Creates a new link for the footnote `reference` and adds the reference to the note order list for proper display at the end of the document.

paragraph (parts)
Source

    # File lib/rdoc/markdown.rb, line 793
    def paragraph parts
      parts = parts.map do |part|
        if "\n" == part then
          RDoc::Markup::HardBreak.new
        else
          part
        end
      end if break_on_newline?

      RDoc::Markup::Paragraph.new(*parts)
    end

Creates an RDoc::Markup::Paragraph from `parts` and including extension-specific behavior

parse (markdown)
Source

    # File lib/rdoc/markdown.rb, line 808
    def parse markdown
      @references          = {}
      @unlinked_references = {}

      markdown += "\n\n"

      setup_parser markdown, @debug
      peg_parse 'References'

      if notes? then
        @footnotes       = {}

        setup_parser markdown, @debug
        peg_parse 'Notes'

        # using note_order on the first pass would be a bug
        @note_order      = []
      end

      setup_parser markdown, @debug
      peg_parse

      doc = result

      if notes? and not @footnotes.empty? then
        doc << RDoc::Markup::Rule.new(1)

        @note_order.each_with_index do |ref, index|
          label = index + 1
          note = @footnotes[ref] or raise ParseError, "footnote [^#{ref}] not found"

          link = "{^#{label}}[rdoc-label:footmark-#{label}:foottext-#{label}] "
          note.parts.unshift link

          doc << note
        end
      end

      doc.accept @formatter

      doc
    end

Parses `markdown` into an RDoc::Document

reference (label, link)
Source

    # File lib/rdoc/markdown.rb, line 855
    def reference label, link
      if ref = @unlinked_references.delete(label) then
        ref.replace link
      end

      @references[label] = link
    end

Stores `label` as a reference to `link` and fills in previously unknown link references.

strong (text)
Source

    # File lib/rdoc/markdown.rb, line 866
    def strong text
      if text =~ /\A[a-z\d.\/-]+\z/i then
        "*#{text}*"
      else
        "<b>#{text}</b>"
      end
    end

Wraps `text` in strong markup for rdoc inline formatting

## Extensions

↑ top

### Public Class Methods

extension (name)
Source

    # File lib/rdoc/markdown.rb, line 603
    def self.extension name
      EXTENSIONS << name

      define_method "#{name}?" do
        extension? name
      end

      define_method "#{name}=" do |enable|
        extension name, enable
      end
    end

Creates extension methods for the `name` extension to enable and disable the extension and to query if they are active.

### Public Instance Methods

break_on_newline ()
Source

    # File lib/rdoc/markdown.rb, line 618
    extension :break_on_newline

Converts all newlines into hard breaks

css ()
Source

    # File lib/rdoc/markdown.rb, line 623
    extension :css

Allow style blocks

definition_lists ()
Source

    # File lib/rdoc/markdown.rb, line 628
    extension :definition_lists

Allow PHP `Markdown` Extras style definition lists

extension (name, enable)
Source

    # File lib/rdoc/markdown.rb, line 705
    def extension name, enable
      if enable then
        @extensions |= [name]
      else
        @extensions -= [name]
      end
    end

Enables or disables the extension with `name`

extension? (name)
Source

    # File lib/rdoc/markdown.rb, line 696
    def extension? name
      @extensions.include? name
    end

Is the extension `name` enabled?

github ()
Source

    # File lib/rdoc/markdown.rb, line 633
    extension :github

Allow Github Flavored `Markdown`

html ()
Source

    # File lib/rdoc/markdown.rb, line 638
    extension :html

Allow HTML

notes ()
Source

    # File lib/rdoc/markdown.rb, line 643
    extension :notes

Enables the notes extension

strike ()
Source

    # File lib/rdoc/markdown.rb, line 648
    extension :strike

Enables the strike extension