Ruby JavaScript Node.js browser Shell HTML Compiler opal js
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opal

Description

Ruby ♥︎ JavaScript

4.4K Stars 315 Forks MIT License 7.3K Commits 153 Opened issues

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Opal

Opal is a Ruby to JavaScript source-to-source compiler.
It also has an implementation of the Ruby corelib and stdlib.

Community:
Stack Overflow Backers on Open Collective Sponsors on Open Collective Gitter Documentation
Code:
Gem Version Build Status (Linux) Build Status (Windows) Code Climate Coverage Status

Usage

See the website for more detailed instructions and guides for Rails, jQuery, Sinatra, rack, CDN, etc. https://opalrb.com.

Compiling Ruby code with the CLI (Command Line Interface)

Contents of

app.rb
:
puts 'Hello world!'

Then from the terminal

$ opal --compile app.rb > app.js # The Opal runtime is included by default
                                 # but can be skipped with the --no-opal flag

The resulting JavaScript file can be used normally from an HTML page:


Be sure to set the page encoding to

UTF-8
inside your
 tag as follows:
<meta charset="utf-8">
<script src="app.js"></script>
…


…

Just open this page in a browser and check the JavaScript console.

Compiling Ruby code from Ruby

Opal.compile
is a simple interface to just compile a string of Ruby into a string of JavaScript code.
Opal.compile("puts 'wow'")  # => "(function() { ... self.$puts("wow"); ... })()"

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

Using Opal::Builder

Opal::Builder
can be used to build the runtime/corelib into a string.
Opal::Builder.build('opal') #=> "(function() { ... })()"

or to build an entire app including dependencies declared with

require
:
builder = Opal::Builder.new
builder.build_str('require "opal"; puts "wow"', '(inline)')
File.write 'app.js', builder.to_s

Compiling Ruby code from HTML (or using it as you would with inline JavaScript)

opal-parser
allows you to eval Ruby code directly from your HTML (and from Opal) files without needing any other building process.

So you can create a file like the one below, and start writing ruby for your web applications.

<meta charset="utf-8">
<script src="https://cdn.opalrb.com/opal/current/opal.js" onload="Opal.load('opal')"></script>
<script src="https://cdn.opalrb.com/opal/current/opal-parser.js" onload="Opal.load('opal-parser')"></script>

<script type="text/ruby">
  puts "hi"
</script>

Just open this page and check the JavaScript console.

NOTE: Although this is possible, this is not really recommended for production and should only be used as a quick way to get your hands on opal.

Running tests

Setup the project:

$ bin/setup

The test suite can be run using:

$ bundle exec 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 start
guard
.

MSpec

MSpec tests can be run with:

$ rake mspec

Alternatively, you can just load up a rack instance using

rackup
, 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's stdlib. It is optional (runs in 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.

opal/

This directory holds the Opal runtime and corelib implemented in Ruby and JavaScript.

stdlib/

Holds the stdlib currently supported by Opal. This includes

Observable
,
StringScanner
,
Date
, etc.

Browser support

  • Internet Explorer 11
  • Firefox (Current - 1) or Current
  • Chrome (Current - 1) or Current
  • Safari (Current - 1) or Current
  • Opera (Current - 1) or Current

Any problems encountered using the browsers listed above should be reported as bugs.

(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 the last 2 versions of Opera. For example, if the current Opera version is 20.x, then we support Opera 12.1x, 19.x and 20.x but not Opera 15.x through 18.x.

Contributors

This project exists thanks to all the people who contribute. contributors

Backers

Thank you to all our backers! 🙏 [Become a backer]

Sponsors

Support this project by becoming a sponsor. Your logo will show up here with a link to your website. [Become a sponsor]

License

(The MIT License)

Copyright (C) 2013-2019 by Adam Beynon and the Opal contributors

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.

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