Question

I am quite new to ruby,

I came across the following code in rails, but I don’t know how the “<<” operator works and what it does in the below code

def <<( rate )
  r = Rating.new
  r.rate = rate
  r.rateable = proxy_owner
  ...
  ...
end
class << ActiveRecord::Base
  ...
  ...
end

Can anybody explain to me?

Edit: here is the code https://github.com/azabaj/acts_as_rateable/blob/master/lib/acts_as_rateable.rb

Answer 1

def <<( rating ):
In your example, this is used to add a rating to a rateable model. (E.g. in acts_as_rateable.rb:41), similar to appending something to a string (str << "abc"). As it is within a module, it will only be included for the models that you declare as rateable.

class << ClassName:

All the methods inside of this block will be static / class methods (see this blog entry). (In this case, all the models will have the methods Model.example_static_method.)