Radius – Powerful Tag-Based Templates¶ ↑

Radius is a powerful tag-based template language for Ruby inspired by the template languages used in MovableType and TextPattern. It uses tags similar to XML, but can be used to generate any form of plain text (HTML, e-mail, etc…).

Usage¶ ↑

With Radius, it is extremely easy to create custom tags and parse them. Here’s a small example:

require 'radius'

# Define tags on a context that will be available to a template:
context = Radius::Context.new do |c|
  c.define_tag 'hello' do
    'Hello world'
  end
  c.define_tag 'repeat' do |tag|
    number = (tag.attr['times'] || '1').to_i
    result = ''
    number.times { result << tag.expand }
    result
  end
end

# Create a parser to parse tags that begin with 'r:'
parser = Radius::Parser.new(context, :tag_prefix => 'r')

# Parse tags and output the result
puts parser.parse(%{A small example:\n<r:repeat times="3">* <r:hello />!\n</r:repeat>})

Output:

A small example:
* Hello world!
* Hello world!
* Hello world!

Quick Start¶ ↑

Read the QUICKSTART file to get up and running with Radius.

Requirements¶ ↑

Radius does not have any external requirements for using the library in your own programs.

Ragel is required to create the ruby parser from the Ragel specification, and both Ragel and Graphviz are required to draw the state graph for the parser.

Installation¶ ↑

It is recommended that you install Radius using the RubyGems packaging system:

% gem install --remote radius

You can also install Radius by copying lib/radius.rb into the Ruby load path.

License¶ ↑

Radius is free software and may be redistributed under the terms of the MIT-LICENSE:

Copyright © 2006-2009, John W. Long

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.

Roadmap¶ ↑

This is a prioritized roadmap for future releases:

1. Clean up the current code base. [Done]

2. Add support for multi-level contexts: tags should be able to be defined to only be valid within other sets of tags. [Done]

3. Create a simple DSL for defining contexts. [Done]

4. Optimize for speed, modify scan.rl to emit C.

Development¶ ↑

The latest version of Radius can be found on RubyForge:

rubyforge.org/projects/radius

Experimental and development versions of Radius can be found on Github:

github.com/jlong/radius

If you are interested in helping with the development of Radius, feel free to fork the project on GitHub and send me a pull request.

John Long

wiseheartdesign.com