From: daz <dooby@...10.karoo.co.uk>
Date: 2003-09-13T22:40:39+09:00
Subject: Re: order of evaluation for method arguments


"ts" <decoux@moulon.inra.fr> wrote:

> >>>>> "d" == daz  <dooby@d10.karoo.co.uk> writes:
>
> d> "Michael Garriss" <mgarriss@earthlink.net> wrote:
>
> >> a = [1,2,3,4,5]
> --> [1, 2, 3, 4, 5]
> >> b = [a.shift,a.shift,a.shift,a.shift,a.shift]
> --> [1, 2, 3, 4, 5]
> >>
>
> d> Well, since:
>
> d>    a, b = b, a
>
> d> is 'defined' (in the sense that it's a ruby idiom),
> d> your example works the way I'd expect, even though
> d> Matz has guarded his options.
>
>  I don't see the relation between the two.
>
>  The first modify `a' in the RHS, the second not.
>
>  Perhaps, it can exist a version of ruby which give
>
>  b = [5, 4, 3, 2, 1]
>
>  and where
>
>  a, b = b, a
>
>  still work
>
>
> Guy Decoux
>
>


I defer, of course ;)

I was merely trying to convey that Ruby evaluates all
RHS (in sequence) before assigning to LHS and it's
no accident (indeed sensible) that:

r = [1,2,3]

a, b = r.shift, r.shift
p [a, b]

#-> [1, 2]



daz