From: Harrison Reiser <y2kbugxp90@...>
Date: 2007-04-14T08:27:37+09:00
Subject: Re: Question about Fixnum

Hah!  Much makes sense now.  I was often curious as to why Fixnums'
object IDs are always equal to 2*n+1; the ID is also the storage
mechanism.  Thanks for this.

Harrison Reiser

On 4/13/07, Gary Wright <gwtmp01@mac.com> wrote:
>
> On Apr 13, 2007, at 1:36 PM, Tim Pease wrote:
> > Fixnum objects are immediate objects in the Ruy source code (other
> > immediate objects are nil, true, false, and symbols). These immediate
> > objects occupy 4 bytes of storage (unsigned long) on most machines.
> > They are accessed by casting and bit shifting in the Ruby source code.
>
> As long as you think of this description ('immediate objects') as
> entirely an implementation issue, I think it is useful.  When you
> switch to talking about Ruby language semantics, I think it is
> better to simply think of Fixnum objects and references as the same
> as all other Ruby objects and references. Same for NilClass,
> FalseClass, and TrueClass. The differences are that the language
> provides literal representations of these references
> (-1,0,1,nil,false,true) and also ensures that object identity and
> object equivalence are the same for their respective classes (for
> example, #dup has no meaning for these objects and you can't create
> new instances of NilClass, FalseClass, and TrueClass).
>
> Gary Wright
>
>
>
>
>