An internal DSL (often called an Embedded DSL) is a DomainSpecificLanguage that is written inside an existing host language. It's a common way of thinking in a number of programming language communities - particularly the Lisp community. It's now gaining a lot of attention as DSLs are a common way of thinking in the rapidly growing Ruby community.

using RSpec::Parameterized::TableSyntax where(:a, :b, :answer) do 1 | 2 | 3 5 | 8 | 13 0 | 0 | 0 end

Notice that the HTML elements (BUTTON, DIV, etc.) are in CAPS. We know this is bending the standard Ruby style rules slightly, but we think it reads better this way.

You can use the match method with the :via option to match multiple verbs at once:

But where is the helper method defined? What’s its visibility? Can I put it in a module? Can I use inheritance? Who can call it? Can I call super from the extracted method? If so, where does super go?