Writing Type Specifications

What are typespecs?

While Elixir isn’t a statically typed language, it does give the ability to specify types using typespecifications, or typespecs. Typespecs are specifications that communicate the intended use of a function.

For example, a function add/2 that adds two numbers a and b might have the following specification:

Notice the syntax used to declare a specification. We use the @spec attribute to indicate that we’re defining a specification, and then declare the parameter types and the return type of the function. The syntax is similar to the syntax you used in the lesson Creating the Problem Behaviour, to define callbacks for your Problem ...