Opal

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Opal is a ruby to javascript source-to-source compiler. It also has an implementation of the ruby corelib.

Opal is hosted on github, and there is a Freenode IRC channel at #opal, ask questions on stackoverflow (tag #opalrb).

Usage

See the website, http://opalrb.org.

Compiling ruby code

Opal.compile is a simple interface to just compile a string of ruby into a string of javascript code.

Opal.compile("puts 'wow'")  # => "(function() { ... })()"

Running this by itself is not enough, you need the opal runtime/corelib.

Building the corelib

Opal::Builder can be used to build the runtime/corelib into a string.

Opal::Builder.build('opal') #=> "(function() { ... })()"

Running compiled code

You can write the above two strings to file, and run as:

<!DOCTYPE html>
<html>
  <head>
    <script src="opal.js"></script>
    <script src="app.js"></script>
  </head>
</html>

Just open a browser to this page and view the console.

Running tests

First, install dependencies:

$ bundle install

RubySpec related repos must be cloned as a gitsubmodules:

$ git submodule update --init

The test suite can be run using (requires phantomjs):

$ rake

This will command will run all RSpec and MSpec examples in sequence.

Automated runs

A Guardfile with decent mappings between specs and lib/corelib/stdlib files is in place. Run bundle exec guard -i to have it started.

MSpec

MSpec tests can be run with:

$ rake mspec

Alternatively, you can just load up a rack instance using rackup spec/config.ru, and visit http://localhost:9292/ in any web browser.

Rspec

RSpec tests can be run with

$ rake rspec

Code Overview

What code is supposed to run where?

  • lib/ code runs inside your ruby env. It compiles ruby to javascript.
  • opal/ is the runtime/corelib for our implementation (runs in browser)
  • stdlib/ is our implementation of ruby stdlib. It is optional (for browser).

lib

The lib directory holds the opal parser/compiler used to compile ruby into javascript. It is also built ready for the browser into opal-parser.js to allow compilation in any javascript environment.

corelib

This directory holds the opal runtime and corelib implemented in ruby and javascript.

stdlib

Holds the stdlib that opal currently supports. This includes Observable, StringScanner, Date, etc.

spec

  • rubyspecs (file) a whitelist of RubySpec files to be ran
  • corelib RubySpec examples (submodule)
  • stdlib rubysl-* examples (submodules)
  • filters The list of MSpec/RubySpec examples that are either bugs or unsupported
  • opal opal additions/special behaviour in the runtime/corelib
  • cli specs for opal lib (parser, lexer, grammar, compiler etc)

Browser support

  • Internet Explorer 6+
  • Firefox (Current - 1) or Current
  • Chrome (Current - 1) or Current
  • Safari 5.1+
  • Opera 12.1x or (Current - 1) or Current

Any problem above browsers should be considered and reported as a bug.

(Current - 1) or Current denotes that we support the current stable version of the browser and the version that preceded it. For example, if the current version of a browser is 24.x, we support the 24.x and 23.x versions.

12.1x or (Current - 1) or Current denotes that we support Opera 12.1x as well as last 2 versions of Opera. For example, if the current Opera version is 20.x, we support Opera 12.1x, 19.x and 20.x but not Opera 15.x through 18.x.

Cross-browser testing sponsored by BrowserStack.

License

(The MIT License)

Copyright (C) 2013 by Adam Beynon

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.