Metaprogramming Ruby 2

A History of Complexity

Instead of looking at the current implementation of attribute methods, let me go all the way back to 2004—the year that Rails 1.0.0 was unleashed on an unsuspecting world.

Rails 1: Simple Beginnings

In the very first version of Rails, the implementation of attribute methods was just a few lines of code:

gems/activerecord-1.0.0/lib/active_record/base.rb

module ActiveRecord
  class Base
    def initialize(attributes = nil)
      @attributes = attributes_from_column_definition
      # ...
    end

    def attribute_names
      @attributes.keys.sort
    end

    alias_method :respond_to_without_attributes?, :respond_to?

    def respond_to?(method)
      @@dynamic_methods ||= attribute_names +
 attribute_names.collect { ...