Programming Elixir ≥ 1.6

The Available Types

You can define implementations for one or more of the following types:

Any	Atom	BitString	Float	Function
Integer	List	Map	PID	Port
Record	Reference	Tuple

The type BitString is used in place of Binary.

The type Any is a catchall, allowing you to match an implementation with any type. Just as with function definitions, you’ll want to put the implementations for specific types before an implementation for Any.

You can list multiple types on a single defimpl. For example, the following protocol can be called to determine whether a type is a collection:

protocols/is_collection.exs

defprotocol Collection do
  @fallback_to_any true
  def is_collection?(value)
end

defimpl Collection, for: [List, Tuple, BitString, Map] do