From: Charles Mills <cmills@...>
Date: 2005-01-09T07:16:24+09:00
Subject: Re: multiple values & variable assignment

Robert Klemme wrote:
> "itsme213" <itsme213@hotmail.com> schrieb im Newsbeitrag
> news:WkJDd.9898$ho.9719@fe2.texas.rr.com...
> > Why does
> >    def f; 1, 2, 3; end
>
> You sure, that this is the code you use?
>
> >> def f; 1, 2, 3; end
> SyntaxError: compile error
> (irb):49: syntax error
> def f; 1, 2, 3; end
>          ^
>         from (irb):49
>         from (null):0
>
> I'll use
>
> >> def f; return 1, 2, 3; end
> => nil
>
> >    x,y,z = f
> > give x=1, y=2, z=3
> >
> > While
> >    x = f
> > gives x=[1, 2, 3]?
>

You can think of it as return splat.  Looks like Ruby 2.0 will give you
piece of mind, see below...

> It's an optimization to save typing: if there are multiple values and
on one
> side there is only one value "*" is automatically prepended:
>
> >> x = f
> => [1, 2, 3]
> >> x
> => [1, 2, 3]
> >> x = *f
> => [1, 2, 3]
> >> x
> => [1, 2, 3]
>
> If you want just the first element you got to do
>
> >> x, = f
> => [1, 2, 3]
> >> x
> => 1

(...)

I think this is the same issue as
irb> def yields
irb> yield(1,2)
irb> end
=> nil
irb> yields { |a| puts a.inspect }
(irb):4: warning: multiple values for a block parameter (2 for 1)
from (irb):2
[1, 2]
=> nil

More info on this here:
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-dev/23568

I know there is an English version of that post somewhere, but I can't
find it on google...

-Charlie