Built-in Protocols

Introduction

Elixir comes with the following protocols:

• Enumerable
• Collectable
• Inspect
• List.Chars
• String.Chars

To play with these, let’s work with MIDI files for the next few lessons.

Example

A MIDI file consists of a sequence of variable-length frames. Each frame contains a four-character type, a 32-bit length, and then length bytes of data.

We’ll define a module that represents the MIDI file content as a struct because the struct lets us use it with protocols. The file also defines a submodule for the individual frame structure.