domain specific languages

The very first time I've hear about DSLs was after the Thoughtworks Boot Camp in March/2012.

I've read some articles after that, but I just really understood it after I started using Capybara.

Capybara is a framework for testing user interaction in rails applications.

A Capybara test will have statements like these:

visit "/"
click_link "My account"

fill_in "Your email", with: "john@example.org"
fill_in "Your password", with: "test"
click_button "Login"

Those statements are part of the Capybara framework. They are part of a language that was created specifically for the purpose of testing web applications. This is the Capybara DSL. A small language created for this specific purpose, or domain.

I've read that DSLs are not a new topic, but with the popularity of dynamic languages like Ruby, they are easy to create and incredibly useful. I'll try to create my own in the near future.