From: "Simon Kröger" <SimonKroeger@...>
Date: 2006-05-21T19:56:52+09:00
Subject: Re: How to intercept all function calls of a object?

uncutstone wu wrote:
> What I want is something like this:
> 
> [...code...]
> 
> Then I can get this kind of result:
> 
> call method hello of class HelloBye
> hello
> return from method hello of class HelloBye
> 
> And similar thing for 'bye' and other methods if existed in object a.

Some food for thoughts:
------------------------------------------------------------
def intercept obj
  meth = obj.methods - %w{__send__ __id__}
  klass, name = class << obj; self; end, obj.class.name
  meth.each do |m|
    klass.module_eval %[
    def #{m} *a,&b
      puts 'in #{name}##{m}'
      super
      puts 'out #{name}##{m}'
    end]
  end
  obj
end

class HelloBye
  def hello
    puts "hello"
  end
  def bye
    puts "byebye"
  end
end

a = HelloBye.new
intercept a #add an intercptor to a
a.hello
a.bye
------------------------------------------------------------

in HelloBye#hello
hello
out HelloBye#hello
in HelloBye#bye
byebye
out HelloBye#bye

method missing would also be an option of course, but wrapping an
object into another one has several drawbacks (e.g. dup and friends
don't work as expected anymore)

cheers

Simon