Programming Elixir

Specs for Functions and Callbacks

The @spec specifies a function’s parameter count, types, and return-value type. It can appear anywhere in a module that defines the function, but by convention it sits immediately before the function definition, following any function documentation.

We’ve already seen the syntax:

@spec function_name( param1_type, …) :: return_type

Let’s see some examples. These come from the built-in Dict module.

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