Playing with modules and bindings

modules.rb

class Configuration
  attr_reader :name

  def initialize(name)
    @name = name
  end
end

class ModuleBuilder
  def self.call(name)
    configuration = Configuration.new(name)

    Module.new.tap do |mod|
      included_method(mod, configuration)
      string_instance_method(mod, configuration)
      proc_instance_method(mod, configuration)
    end
  end

  def self.included_method(mod, config)
    mod.module_eval do
      # Using nested procs
      # meth = ->(object) do
      #   puts ">> config: #{config}"
      #   puts ">> #{self.name} included in #{object.name}"
      #
      #   # define overide class method
      #   override_meth = ->() do
      #     puts ">> cm config: #{config}"
      #     puts ">> class method defined in #{self.name}"
      #   end
      #   object.send :define_singleton_method, :cm, override_meth
      # end
      #
      # self.send :define_singleton_method, :included, meth

      # Since we're in the module we can use define_singleton_method directly
      define_singleton_method :included do |object|
        puts ">> config: #{config}"
        puts ">> #{self.name} included in #{object.name}"

        # define overide class method
        override_meth = ->() do
          puts ">> cm config: #{config}"
          puts ">> class method defined in #{self.name}"
        end
        object.send :define_singleton_method, :cm, override_meth
      end
    end
  end

  def self.string_instance_method(mod, config)
    mod.module_eval(%Q{
      def im_string
        puts ">> instance method defined with string eval in Module #{config.name}"
      end
    })
  end

  def self.proc_instance_method(mod, config)
    mod.module_eval do
      meth = ->() { puts ">> instance method defined with proc in Module #{config.name}" }
      self.send :define_method, :im_proc, meth
    end
  end
end

FooModule = ModuleBuilder.call(:foo)

BarModule = ModuleBuilder.call(:bar)

class A
  def self.cm
    puts ">> class method defined on A"
  end

  def im
    puts ">> instance method defined in Class A"
  end
end

class B < A
  include FooModule
end

class C < A
  include BarModule
end


# >> config: #<Configuration:0x007f88040206a0>
# >> FooModule included in B
# >> config: #<Configuration:0x007f880401bbc8>
# >> BarModule included in C

A.cm
# >> class method defined on A

A.new.im
# >> instance method defined in Class A

B.cm
# >> cm config: #<Configuration:0x007f88040206a0>
# >> class method defined in B

B.new.im
# >> instance method defined in Class A

B.new.im_string
# >> instance method defined with string eval in Module foo

B.new.im_proc
# >> instance method defined with proc in Module foo

C.cm
# >> cm config: #<Configuration:0x007f880401bbc8>
# >> class method defined in C

C.new.im
# >> instance method defined in Class A

C.new.im_string
# >> instance method defined with string eval in Module bar

C.new.im_proc
# >> instance method defined with proc in Module bar