From: Rick DeNatale <rick.denatale@...>
Date: 2007-09-18T01:33:24+09:00
Subject: Re: Newbie help

On 9/17/07, 7stud -- <dolgun@excite.com> wrote:
> David A. Black wrote:
> > Hi --
> >
> > On Mon, 17 Sep 2007, 7stud -- wrote:
> >
> >>
> >>       |
> >>   symbol_obj
> >>   id:2545934
> >>   ^   ^   ^
> >>   |   |   |
> >>   s1  s2  s3
> >
> > If the top arrow means that the symbol :hello contains a reference to
> > a string "hello", in the same way that s1-3 are bound to references to
> > :hello, then I would say that's the error.
>
> Yes, the arrows stand for references.
>
> > A symbol can be converted
> > to a string, such that the string represents the same sequence of
> > characters as the symbol; but the symbol is not a reference to a
> > string object.
> >
>
> Interesting and puzzling.  The symbol object has no member variable that
> is a pointer to a string?  As a consequence, the string object might
> never exist in memory?

The exact situation is implementation dependent and the implementation
of symbols in Ruby has changed over time.

In general the interpreter/vm needs to be able to obtain the string
representation of a symbol, and also obtain/create a symbol from an
arbitrary string.  There are several ways to achieve these
requirements.

I guess that it's literally true that in a minimal program like

   :symbol

A string object "Symbol" might never exist in memory, but SOME
representation of that sequence of characters almost certainly does.

-- 
Rick DeNatale

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