Enumerable

The Enumerable protocol is the basis of all the functions in the Enum module. Any type implementing it can be used as a collection argument to Enum functions.

We’re going to implement Enumerable for our Midi structure, so we’ll need to wrap the implementation in something like this:

defimpl Enumerable, for: Midi do 
  # ...
end

Major functions

The protocol is defined in terms of four functions: count, member?, reduce, and slice, as shown below:

defprotocol Enumerable do
  def count(collection)
  def member?(collection, value) 
  def reduce(collection, acc, fun) 
  def slice(collection)
end

The count function returns the number of elements in the ...