What's the nature of "property" in a Ruby class?

Question

I don't understand the keywords like attr_reader or property in the following example:

class Voiture 
  attr_reader :name
  attr_writer :name
  property :id, Serial
  property :name, String
  property :completed_at, DateTime
end

How do they work? How can I create my own? Are they functions, methods?

class MyClass 
    mymagickstuff :hello
end

Answer 1

That are just class methods. In this example has_foo adds a foo method to an instance that puts a string:

module Foo
  def has_foo(value)
    class_eval <<-END_OF_RUBY, __FILE__, __LINE__ + 1
      def foo
        puts "#{value}"
      end
    END_OF_RUBY
  end
end

class Baz
  extend Foo
  has_foo 'Hello World'
end

Baz.new.foo   # => Hello World