Adzz

defprotocol Add do
  def calculate(a, b)
end

# Now we can define implementations of it for the various kinds of
# data types we might get inside our collections that we are zipping.

defimpl Add, for: Integer do
  def calculate(a, b) when is_integer(b), do: a + b
end

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defprotocol Zip do
  def apply(collection_1, collection_2, operation)
end

# We can implement it for lists:
defimpl Zip, for: List do
  def apply(a, b, calculate) do
    Enum.zip(a, b)
    |> Enum.map(fn {a, b} -> calculate.(a, b) end)
  end

Adzz

list_1 = [1, 2]
list_2 = [3, 4]

Zip.apply(list_1, list_2, fn x, y -> x + y end) #=> [4, 6]

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defmodule Test do
  def thing() do
    1+1
  end
  
  defmacro my_macro do
    quote do
      1 + 1
    end
  end

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response = %{"meat_type" => "medium rare", "pickles" => false, "collection_date" => "2019-11-04"}

# We want a struct so that we can do things like implement protocols for it
defmodule SteamedHam do
  defstruct [:meat_type, :pickles, :collection_date]
end

# With no !, the struct function selects only the fields defined in the schema.
steamed_ham = struct(SteamedHam, response)

Adzz

defmodule AmazeOn do
  defstruct [price: 10]
end

defmodule Area do
  defstruct []
end

defmodule Square do
  defstruct [:side]

Adzz

defmodule Perimeter do
  defstruct []
end

defprotocol PerimeterProtocol do
  def calculate(shape)
end

defimpl Shape, for: Perimeter do
  def calculate(%Perimeter{}, shape) do

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defmodule Circle do
  defstruct [:radius]
end

defimpl AreaProtocol, for: Circle do
  def calculate(%Circle{radius: radius}) do
    3.14 * radius * radius
  end
end

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defmodule Square do
  defstruct [:side]
end

defmodule Area do
  defstruct []
end

defprotocol Shape do
  def calculate(calculation, shape)

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Shape.calculate(:area, %Square{side: 10})