From: Daniel Martin <martin@...>
Date: 2006-08-19T02:48:28+09:00
Subject: Re: [QUIZ] QAPrototype (#91)

Ruby Quiz <james@grayproductions.net> writes:

> [Editor's Note:
>
> I envision this could actually be handy for prototyping classes IRb.  Bonus
> points if you can later print the source for all methods interactively defined.
>
> --JEG2]

Yeah, I was thinking about that as I read this quiz - the core of the
solution seems obvious, though I'm sure we'll see a bunch of
variation.  What really seems interesting to me, though, is the
different ways you could extend this with little helper methods that
are useful when you're writing a prototype method, such as:

def warn_caller_obsolete(current_meth,*args)
  call_line = caller[1]
  called_meth = caller[0].gsub(/^[^`]*`([^']+)'.*/,'\1')
  warn "#{call_line}: `#{called_meth}' is obsolete; use `#{current_meth}'"
  self.send(current_meth,*args)
end

Then, you can do things like this:

irb(main):039:0> def b(f); [[f],f]; end;
irb(main):040:0* def a(f); warn_caller_obsolete(:b,f); end;
irb(main):041:0* a(9)
(irb):41:in `irb_binding': `a' is obsolete; use `b'
=> [[9], 9]

(Say, whatever happened to the call_stack RCR?)

Similar helper methods could do things like simply log the call for
later (assuming the caller can handle getting "nil" back) or delegate
the call along to some other object, possibly while logging the fact.
(Okay, that last one is probably not of much use)

I can imagine a future ruby IDE that would give the option to pop open
an editor when this happened.