Question

Why is this code according to the documentation works ?
http://api.rubyonrails.org/classes/ActiveRecord/Scoping/Named/ClassMethods.html

class Article < ActiveRecord::Base
  scope :featured, where(:featured => true)

  def self.titles
    map(&:title)
  end
end

Article.featured.titles

In my console gets:

NoMethodError: undefined method `map' for #<Class:0xb70bfb0>

Answer 1

My initial answer was the right one: it can’t work…

I guess I finally convinced myself because docs should rule…

Well, I think what’s important in the doc is the idea: you can chain scopes with class methods.

But the implementation of the class method given in example is definitely wrong.