# Ruby Document format

RD (Ruby Document) is a lightweight markup language for writing Ruby-related documents. It can be embedded in Ruby source code.
RD is a traditional format. In modern Ruby, developers tend to write documents in RDoc instead of RD.

## Use

Originally, most documentation in the Ruby world, including for Ruby itself, had been written in RD. Then in 2002, much of it was converted to RDoc format. Although, the Japanese version of the Ruby Reference Manual still remains in RD format.
RD is designed to be written by hand and easily read in its raw form. Most end-users however experience it after it has been converted into HTML or man pages.
RD can be embedded in Ruby code, and pure RD files usually have the extension .rd.

## Sample RD document

This document is syntactically correct RD, which attempts to follow the major conventions on section naming as well.
| Source | HTML result |
| =begin = NAME RD sample - A sample RD document = SYNOPSIS <syntaxhighlight lang="ruby" class="" style="background:none; border:none; color:inherit; padding: 0px 0px;" inline="1">here.is_a?(Piece::Of::Code)</syntaxhighlight> <syntaxhighlight lang="ruby" class="" style="background:none; border:none; color:inherit; padding: 0px 0px;" inline="1">print <<"END"</syntaxhighlight> This indented block will not be scanned for formatting codes or directives, and spacing will be preserved. END = DESCRIPTION Here's some normal text. It includes text that is ((*emphasized*)), ((%keyboard%)), (({code}))-formatted, ((|variable part|)), ((:indexed:)), and (('as-is'))((-footnote-)). == An Example List * This is a bulleted list. * Here's another item. * Nested list item. == An ordered List (1) This is the first item (2) second * Nested unordered list. (3) third (1) Nested ordered list (2) its second item =end =begin html <syntaxhighlight lang="html" class="" style="background:none; border:none; color:inherit; padding: 0px 0px;" inline="1"><img src="Example.png" align="right" alt="Figure 1." /></syntaxhighlight> <syntaxhighlight lang="html" class="" style="background:none; border:none; color:inherit; padding: 0px 0px;" inline="1"><p></syntaxhighlight> Here's some embedded HTML. In this block I can <syntaxhighlight lang="html" class="" style="background:none; border:none; color:inherit; padding: 0px 0px;" inline="1">include images, apply <span style="color: green"></syntaxhighlight> <syntaxhighlight lang="html" class="" style="background:none; border:none; color:inherit; padding: 0px 0px;" inline="1">styles</span>, or do anything else I can do with</syntaxhighlight> HTML. RD processors that aren't outputting HTML will completely ignore it. <syntaxhighlight lang="html" class="" style="background:none; border:none; color:inherit; padding: 0px 0px;" inline="1"></p></syntaxhighlight> =end =begin = COPYRIGHT Copyright 2005 [[J. Random Hacker]] <jrh@cpan.org>. Permission is granted to copy, distribute and/or modify this document under the terms of the [[GNU Free Documentation License]], Version 1.2 or any later version published by the [[Free Software Foundation]]; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. =end | NAME RD sample - A sample RD document SYNOPSIS here.is_a?(Piece::Of::Code) print <<"END" This indented block will not be scanned for formatting codes or directives, and spacing will be preserved. END DESCRIPTION Here's some normal text. It includes text that is emphasized, keyboard, code-formatted, variable part, indexed, and as-is$^{*1}$. An Example List This is a bulleted list. Here's another item. Nested list item. An ordered List This is the first item second Nested unordered list. start=3third Nested ordered list its second item Here's some embedded HTML. In this block I can include images, apply styles, or do anything else I can do with HTML. RD processors that aren't outputting HTML will completely ignore it. COPYRIGHT Copyright 2005 J. Random Hacker <jrh@cpan.org>. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. |