From: Robert Klemme <bob.news@...>
Date: 2004-01-25T04:54:58+09:00
Subject: Re: determine method passed and determine the receiver that received the method


"Pe�a, Botp" <botp@delmonte-phil.com> schrieb im Newsbeitrag
news:1030AB5FAD0A3847B7B1F7B93332AFB501E18290@bgmail00.delmonte-phil.com...
> Hi Friends,
>
> Forgive me in adv for asking a newbie question.
>
> 1. First question: How do I get the the method passed?
>
> Eg.
>
> >cat test1.rb
> #-------------------------
> class Dog
>    def bark
>        'arf!arf!'
>    end
>    def method_missing(x)
> p "method missing"
>        "sorry, cannot do #{x} in #{self}"
>    end
> end
>
> beethoven = Dog.new
> p beethoven.bark
> p beethoven.purr
> #-------------------------
>
> >ruby -w test1.rb
> "arf!arf!"
> "sorry, cannot do purr in #<Dog:0x2777228>"
>
>
> I'd like a method similar to method_missing(x) (wherein the methodname is
> passed in x), but only access it before a method is run (maybe name it
> method_called(x)).
>
> So I can do (maybe),
>
> ..
> Class Dog
> ..
>    def method_called(x)
>        p "You ask for #{x}"
>    end
> end

Tracing is one option. See
http://www.rubycentral.com/book/ref_m_kernel.html#Kernel.set_trace_func

Another option is to use a similar scheme as in Delegator and automatically
generate proxy methods that invoke your "method_called" just before they
hand over control to the real method.
http://www.rubycentral.com/book/lib_patterns.html

Which of the approaches you choose depends on your situation.

Tehre might be another option to define a module / class method that
automatically creates a new method that first invokes method_called and the
the original method.  Sorryy, I don't have the time at the moment to put
such a thing together.

As an additional information: there is a feature in the makes that allows to
define before, after and around hooks for method invocations which would
enable you to do similar things.

Regards

    robert