ex_align

defmodule Example.Macros do
  defmacro field(name, type, opts \\ []) do
    quote do
      @fields {unquote(name), unquote(type), unquote(opts)}
    end
  end

  defmacro validate(field, rule) do
    quote do
      @validations {unquote(field), unquote(rule)}
    end
  end

  defmodule Schema do
    import Example.Macros

    field :id,     :integer, primary_key: true
    field :name,   :string,  required:    true
    field :email,  :string,  required:    true
    field :age,    :integer, default:     nil
    field :active, :boolean, default:     true

    validate :name,  :presence
    validate :email, :format
    validate :age,   :numericality
  end
end