From: Chad Perrin <perrin@...>
Date: 2007-03-17T07:42:31+09:00
Subject: Re: yield

On Sat, Mar 17, 2007 at 07:36:21AM +0900, Corey Konrad wrote:
> Brian Candler wrote:
> > On Sat, Mar 17, 2007 at 07:10:26AM +0900, Corey Konrad wrote:
> >> 
> >> def printer(arg)
> >>   yield arg
> >> end
> >> 
> >> printer("ball")
> >> printer {|word| puts word}
> >> 
> >> why is that, cant yield be used with arguments?
> > 
> > It can. Your second function 'printer' takes one argument plus one 
> > block.
> > However in the first case you were calling it without a block, and in 
> > the
> > second case you were calling it without an argument.
> > 
> > What you need is:
> > 
> >   printer("ball") {|word| puts word}
> 
> oh ok, my understanding for some reason was that the method was going to 
> remmeber that i set arg to "ball" so that when i used printer with the 
> block that "ball" would still be in arg. So is that why it isnt working, 
> is because when i call the printer method the second time the value 
> stored in arg is destroyed?

I'm just guessing here, but . . .

It looks like you're expecting something akin to class behavior from a
method.  Perhaps what you want to do is something more like this:

class Printer
  def initialize(arg)
    @arg = arg
  end

  def iterator_thingie
    yield @arg
  end
end

printer = Printer.new("ball")
printer.iterator_thingie {|word| puts word}


Then again, maybe that's not the kind of behavior you want.

-- 
CCD CopyWrite Chad Perrin [ http://ccd.apotheon.org ]
print substr("Just another Perl hacker", 0, -2);