Ruby: Calling class method from instance

Question

In Ruby, how do you call a class method from one of that class\'s instances? Say I have

class Truck
  def self.default_make
    # Class method.
    \"mac\"
  end         


        

Answer 1

Here's an approach on how you might implement a _class method that works as self.class for this situation. Note: Do not use this in production code, this is for interest-sake :)

From: Can you eval code in the context of a caller in Ruby? and also http://rubychallenger.blogspot.com.au/2011/07/caller-binding.html

# Rabid monkey-patch for Object
require 'continuation' if RUBY_VERSION >= '1.9.0'
class Object
  def __; eval 'self.class', caller_binding; end
  alias :_class :__
  def caller_binding
    cc = nil; count = 0
    set_trace_func lambda { |event, file, lineno, id, binding, klass|
      if count == 2
        set_trace_func nil
        cc.call binding
      elsif event == "return"
        count += 1
      end
    }
    return callcc { |cont| cc = cont }
  end
end

# Now we have awesome
def Tiger
  def roar
    # self.class.roar
    __.roar
    # or, even
    _class.roar
  end
  def self.roar
    # TODO: tigerness
  end
end

Maybe the right answer is to submit a patch for Ruby :)