module SuperSecretMethods
  extend self

  def singleton_def_bad
    #begin-snippet: singleton_def_bad
    def secret.squirrel
      :shhh
    end
    #=> undefined local variable or method `secret' (NameError)
    #end-snippet
  end

  def singleton_def_ok
    #begin-snippet: singleton_def_ok
    secret = "hello"
    def secret.squirrel
      :shhh
    end

    p secret #=> "hello"
    p secret.squirrel #=> :shhh
    #end-snippet
    secret
  end

  def define_method_with_dot(receiver)
    receiver.instance_eval do
      #begin-snippet: define_method_with_dot
      # this works
      define_method('secret.squirrel') do
        :shhh
      end
      #end-snippet
    end
  end

  def call_secret_method_bad
    #begin-snippet: call_secret_method_bad
    secret.squirrel
    #=> undefined local variable or method `secret' (NameError)
    #end-snippet
  end

  def call_secret_method_ok(receiver)
    receiver.instance_eval do
      return begin
        #begin-snippet: call_secret_method_ok
        p send('secret.squirrel') #=> :shhh
        #end-snippet
      end
    end
  end

  def bad_ivar_set
    #begin-snippet: bad_ivar_set
    instance_variable_set("@secret.squirrel", :shhh)
    #=> NameError: `@secret.squirrel' is not allowed as an instance variable name
    #end-snippet
  end

  def bad_const_set
    #begin-snippet: bad_const_set
    String.const_set('SECRET.SQUIRREL', :shhh)
    #=> NameError: wrong constant name SECRET.SQUIRREL
    #end-snippet
  end
end