Ruby ProTip: Better DSL’s

January 24, 2011 by nickmulder comments

DSL’s in Ruby are easy to build. What I am about to show you is far from new, but it’s a great trick and its worth the refresher.

Consider this DSL

http://gist.github.com/790023

Now consider this DSL

http://gist.github.com/790024

There is one subtle difference, we don’t need the f’s! Here is how to pull it off:

http://gist.github.com/790027

You could also support both if you wanted:

http://gist.github.com/790029

When building a DSL it’s better not to be wishy-washy. Choose one version and stick to it.

I prefer the instance_eval version. (Though I will typically use Proc.new to capture the block. More on that later.)

@nickmulder