Skip to main content

Opal - Ruby to JavaScript compiler

So I just found out about the Opal Ruby to JavaScript compiler and I am very intrigued.

http://opalrb.org/

So for a few years now, the Ruby community has been encouraged to use CoffeeScript as a JavaScript "alternative" (http://coffeescript.org/) but for some reason, as an avid JavaScript programmer, it never appealed to me. CoffeeScript offers a small amount of syntactic sugar on top of JavaScript, but it never seemed worth the learning curve for me to take it on. I don't actually mind JS's brackets (as they let you know where things begin and end cleanly) and significant white space in a programming language has always seemed like a bad idea too (it's bad enough that a misplaced semicolon can stop a program from running properly, but try searching for an extra white space character you can't even see!).

Opal on the other hand, is actually Ruby compiled to JavaScript (not Ruby/Python-ish syntax). It looks, feels, and even smells like Ruby because it is. The JavaScript it generates might be a little more verbose than that generated by CoffeeScript, but that's because it has to do more (Ruby and JavaScript are separate languages in the proper sense, not different dialects). It does however compile out its classes using the module pattern which means it is safely scoped (http://toddmotto.com/mastering-the-module-pattern/).

It also has a "Native" bridge to interact with regular JavaScript which helps maintain clean separation (http://opalrb.org/docs/interacting_with_javascript/) as well as RSpec support for testing. It even supports method_missing.

In any case, there are many other interesting things about it, which I won't go into here.

It will be interesting to see where it leads...

PS I see Opal as being more like ASM.js (http://asmjs.org/) than CoffeeScript. It can actually use a quite limited subset of JS in order to be functional.

Comments

Popular posts from this blog

Freezing Gems

What is a gem and why would you want to freeze it?

In Ruby, there are times when you want to access pieces of functionality that other people of written (3rd party libraries) and you normally have 2 options. You can install a plug in or install a gem. Normally the method you use is determined by which ever is made available by the author.

Gems are installed on the host machine and are pretty handy when you want to run things in the command line or else across lots of projects, but their downside is that if you use a gem in a Rails project there is no automatic publishing mechanism when you deploy your site. You will need to log onto the remote host machine and install the gem manually.

Plugins are specific to Rails and are similar to gems in that they are also 3rd party libraries. However they are associated with your Rails project as opposed to your machine so they will get posted to the server on a regular deploy.

Freezing a gem is the process of transforming a gem into a plug in. Essen…

Unit/Functional Testing RubyAMF

One of my current projects is using RubyAMF to communicate with Flash (http://rubyforge.org/projects/rubyamf/). On the whole this is really nice because it allows you to transfer Ruby objects directly to ActionScript ones (as opposed to translating the object into XML, sending the XML and then recreating the object in ActionScript).
However, Rails does not provide a built in transport mechanism for AMF, so we cannot run functional testing directly on the data call (as we could for an XML or HTML transport layer). This is a show stopper for a lot of people (Rails w/o Unit testing = a big mess of trouble when something goes wrong).
We can though serve both the HTML and the AMF formats depending on the request format. This means that we can test the object instantiation logic and make sure there are no errors in the controllers (though we cannot check the actual format of the data being served). In the controller, instead of rendering AMF alone, do the following respond_to do |format|

Comparing Rails' Active Record Pattern with Phoenix/Elixir/Ecto

Rails has a very well established Active Record pattern for dealing with the database. You have an Active Record model which maps to the database table, the schema of the model comes directly from the database schema and you place your model specific methods on the Active Record model. This file is also where you set your model relationships (e.g. has_many, has_one, belongs_to). Your instance of the model has all the methods built in.

In Ecto/Phoenix it's a little different. First of all, the database schema doesn't automatically map to the "model". In fact we don't really have models (as Elixir is a functional paradigm). What happens in one file in Rails, happens in essentially two (or more). You have a schema file (where you have to list out all the attributes and relationships). Using the schema file, your "instance" is essentially a data structure (with no methods on it). If you want to transform the data on your struct, you would use a context modu…