From: Matt Maycock <ummaycoc@...>
Date: 2004-12-25T04:28:51+09:00
Subject: Re: SimpleDelegate (was Re: Inconsistency with IO.readlines)

> Thank you for walking through this with me.

No prob :-)

> > handle = nil
> > input_reader(some_arg) {|handle| ...}
> > handle.puts "Meow Mix Please Deliver"
> 
> Hmm, but the code I saw was:
> 
> >   block = Proc.new {|source|
> >     getter = SimpleDelegator.new(source)
> >     yield getter
> >     getter.__setobj__(nil)
> >   }
> 
> You're worried that "getter" may have existed outside input_reader(),
> in the calling code, and you want it to be immediately obvious if you
> trample that value?

So I think there's a chance what you're saying is what I meant - but
maybe not (due to natural language ambiguity -- for me arising from
the `but' in your `Hmm, but the code I saw was:')

So the variable block is there make the delegator `getter' - send it
to the block that was invoked with input_reader, and then have
`getter' delegate to nil.  The reason for this is that if you passed
nil or '-' to input_reader, then (had the __set_obj__ not been invoked
after yield), then the `handle' variable above would have been valid
to use as an IO object.  However, this would not be so if a filename
was given (as that IO object would have been closed by the File#open
method after the execution of block#[]).  This way, both forms of
invocation ($stdin and fileIO) behave the same way wrt the block
variable getter that is passed to yield, before and after return from
#input_reader.

So I think that's exactly what you mean - but I just
reworded/reiterated it to make sure.

-- 
There's no word in the English language for what you do to a dead
thing to make it stop chasing you.