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RedCloth - Textile parser for Ruby



Helio Cola


Jason Garber


© 2011 Jason Garber




RedCloth is a Ruby library for converting Textile into HTML.

Attention - Deprecating JRuby and Windows support in version 4.3

In order to prioritize merging a fix for the long standing vulnerability CVE-2012-6684, our new maintainer has elected to stop maintaining the precompiled versions for Windows and JRuby.


RedCloth can be installed via RubyGems:

gem install RedCloth


If you just want to use RedCloth, you do NOT need to build/compile it. It is compiled from C sources automatically when you install the gem on the ruby platform. Precompiled binary gems are provided for JRuby and Win32 platforms prior to version 4.3.

RedCloth can be compiled with rake compile. Ragel 6.3 or greater is required. Again, Ragel is NOT needed to simply use RedCloth.

Supported platforms

By default, the rake compile task builds a native C extension (MRI 1.8 or 1.9). A pure Ruby version can also be generated, but it’s super slow and Ruby 1.8-only, and doesn’t support multi-byte characters.

The RedCloth::EXTENSION_LANGUAGE constant indicates in which language your copy of RedCloth is compiled.


Please submit bugs as issues to this repo.

Using RedCloth

RedCloth is simply an extension of the String class that can handle Textile formatting. Use it like a String and output HTML with its RedCloth#to_html method.

Simple use:

text = "This is *my* text."

Multi-line example:

doc = <<EOD
h2. Test document

Just a simple test.
puts doc.to_html

What is Textile?

Textile is a simple formatting style for text documents, loosely based on some HTML conventions.

Sample Textile Text

h2. This is a title

h3. This is a subhead

This is a bit of paragraph.

bq. This is a blockquote.

Writing Textile

A Textile document consists of paragraphs. Paragraphs can be specially formatted by adding a small instruction to the beginning of the paragraph.

h3.     Header 3.
bq.     Blockquote.
#       Numeric list.
*       Bulleted list.

Quick Phrase Modifiers

Quick phrase modifiers are also included, to allow formatting of small portions of text within a paragraph.

-deleted text-
+inserted text+

==notextile== (leave text alone)

To make a hypertext link, put the link text in “quotation marks” followed immediately by a colon and the URL of the link.

Optional: text in (parentheses) following the link text, but before the closing quotation mark, will become a title attribute for the link, visible as a tool tip when a cursor is above it.


"This is a link (This is a title)":

Will become:

<a href="" title="This is a title">This is a link</a>


To insert an image, put the URL for the image inside exclamation marks.

Optional: text that immediately follows the URL in (parentheses) will be used as the Alt text for the image. Images on the web should always have descriptive Alt text for the benefit of readers using non-graphical browsers.

Optional: place a colon followed by a URL immediately after the closing ! to make the image into a link.



Will become:

<img src="" alt="Textist" />

With a link:


Will become:

<a href=""><img src="/common/textist.gif" alt="Textist" /></a>

Defining Acronyms

HTML allows authors to define acronyms via the tag. The definition appears as a tool tip when a cursor hovers over the acronym. A crucial aid to clear writing, this should be used at least once for each acronym in documents where they appear.

To quickly define an acronym in Textile, place the full text in (parentheses) immediately following the acronym.


ACLU(American Civil Liberties Union)

Will become:

<acronym title="American Civil Liberties Union">ACLU</acronym>

Filtering HTML

RedCloth doesn’t filter unsafe html tags by default, do to this use the following syntax:"<script>alert(1)</script>", [:filter_html]).to_html

which will filter the script tags from the HTML resulting in:


Adding Tables

In Textile, simple tables can be added by separating each column by a pipe.


Styles are applied with curly braces.

table{border:1px solid black}.
{background:#ddd;color:red}. |a|red|row|