From: Robert Feldt <feldt@...>
Date: 2001-03-06T12:45:44+09:00
Subject: [ruby-talk:12076] Re: ANN: Memoize 0.1.2

On Tue, 6 Mar 2001, Avi Bryant wrote:

> So somehow I'm messing up the block_given? call; I'm not sure how.
> Ideas, anyone?
> 
Yes, its kind of strange that it is messed up.
My interpretation of what your trying to do with advice.c is (in Ruby
code with generality taken away):

---
def orig
  puts "hello world"
  puts block_given?
end

def real_call(&b)
  Object.send(:orig)
end

def call_method
  real_call {yield}
end

def call_advice(&b)
  advice(&b)
end

def advice
  puts "pre"
  yield
  puts "post"
end

def dispatch
  call_advice {call_method}
end

dispatch
---

Is that a correct interp?

(BTW, I'm not sure I understand the need for real_call and call_method
with the yield. Cant they be merged? Or will it not work when we want to
alter what is returned from the advice?)

The above code works and does not mess up the block_given? call. I guess
the problem might be in a difference between in how rb_iterate handles the
iter stack as opposed to when the above Ruby code is executed. But my
knowledge of Ruby internals is too limited. Matz or Guy or any other one?

/Robert