Protocols

Introduction

We’ve used the inspect function many times in this course. It returns a printable representation of any value as a binary, which is what we call strings.

But let’s stop and think for a minute. Just how can Elixir, which doesn’t have objects, know what to call to do the conversion to a binary? We can pass inspect anything, and Elixir somehow makes sense of it. It could be done using guard clauses:

def inspect(value) when is_atom(value), do: ...
def inspect(value) when is_binary(value), do: ...
:       :

But there’s a better way.

Elixir has the concept of protocols. A protocol is a little like the ...