From: Rick DeNatale <rick.denatale@...>
Date: 2006-09-25T12:34:27+09:00
Subject: Re: Riddle me this (a question about expressions)

On 9/24/06, dblack@wobblini.net <dblack@wobblini.net> wrote:
> Hi --
>
> On Mon, 25 Sep 2006, Hal Fulton wrote:
>

> >
> > Nevertheless I think it's significant that raise is a method
> > whereas return (of course) is not.
>
> I think so too.  I would not want to see a method call of any kind be
> dealt with as a syntax error just because it has an assignment to its
> left.  Since return can't really be a method (at least my brain can't
> wrap itself around that concept :-) I don't think that the two of them
> need to be thought of together with regard to the syntax-error matter.
>
> > I wonder if there is some case where raise would/does return
> > a meaningful value somehow? My gut reaction is 'no'... but
> > this is Ruby...
>
> I am fairly certain that the return value can never be captured.  At
> least I can't figure out how to do it.
>
> In this:
>
>   def raise_value
>     x = raise
>   rescue
>     x
>   end
>
>   p raise_value   # nil
>
> I'm pretty sure that x is nil because of the thing where the parser
> sees an assignment and defines the variable.  I don't think an
> assignment ever actually takes place -- as witness the fact that:
>
>    x = raise || 1
>
> also leaves x as nil.

But try:

x = raise rescue nil || 1

Of course this is a trivial example, but the point is that raise can
in fact have a value.


-- 
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/