From: Logan Capaldo <logancapaldo@...>
Date: 2006-09-25T13:18:43+09:00
Subject: Re: Riddle me this (a question about expressions)

On Mon, Sep 25, 2006 at 12:34:27PM +0900, Rick DeNatale wrote:
> 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.
> 
def x
 fail "Exception"
end

x = return x() rescue nil

Just muddying the waters.
> 
> -- 
> Rick DeNatale
> 
> My blog on Ruby
> http://talklikeaduck.denhaven2.com/