Using Haml with Rails 3.0

One of the things I [heart] about being a Ruby/Rails developer for ThoughtWorks is that I occasionally get asked to do something really cool on the side, like being a technical reviewer for an upcoming book on Rails 3.0.

In this particular book, the author uses Haml instead of Erb for templating views in the sample code. When I'm reviewing a book, I like to actually exercise as much of the sample code as I reasonably can, as it tends to be among the hardest stuff to get right, and among the easiest ways to discourage a reader when it's not right. But Rails defaults to Erb for templating, and I'm not exactly Haml-enabled.

What's a geek to do?

Well, my friend Google had a thing or two to suggest, but the process is slightly non-trivial so I thought I'd collate it here, thusly:

• NB: All commands are entered from your Rails 3.0 application's root directory.


• Edit [your_app]/Gemfile, and add the line gem 'haml' somewhere convenient.


• Edit [your_app]/config/application.rb, and add the line g.template_engine :haml to the config.generators block (uncommenting the block if necessary).


• gem install haml


• bundle install


• haml --rails .


• git clone git://github.com/psynix/rails3_haml_scaffold_generator.git lib/generators/haml

That last bit is particularly important for allowing Rails' scaffold generators to Do The Haml Thang^(TM) when generating view templates.

Now back to my regularly scheduled tech review ...

P.S.: The book is going to be awesome. Reserve your copy now!