Question

I was wondering if it’s possible to make it so that if I had something like

class Test

  attr_reader :access_times
  def initialize
    @access_times = 0
  end

  def get_two
    2
  end

  ...
end

t = Test.new

That any access to t would run a particular piece of code before actually running the method?

For example, if I suddenly decided to say t.get_two, the fact that I used the . syntax would increment @access_times by 1. Or perhaps I made a check t.is_a?(Test), it would also increment @access_times by 1. Accessing any methods or attributes inherited by Test would also increment the variable by 1.

Basically I want to add some stuff to the . syntax if possible.

I am not asking whether this is good or bad code, just whether it’s possible and how it would be done. I wouldn’t normally use it since I could just add the increment logic to every method manually and replace all direct instance variable accessing with methods (even things like is_a? and other things inherited from Object)

Answer 1

a pretty hardcore-version would be to use set_trace_func: http://apidock.com/ruby/Kernel/set_trace_func

this allows you to subscribe to all the ruby events fired throughout your program, which can be a ton of calls…

i don’t think that there is a build-in hook for registering to arbitrary method-calls. you could implement something with method-missing, method-chaining or delegation, but that would depend on your requirments.