From: why the lucky stiff <ruby-core@...>
Date: 2003-06-21T05:52:36+09:00
Subject: Re: Copying RVALUE

Tanaka Akira (akr@m17n.org) wrote:
> 
> One idea is creating empty array just after the anchor.
> 

This is an idea, though I'd like something more general.  The anchor
could be an array, a hash, an object, a struct, anything with depth.
Using that technique, everytime I want to support some new kind of
RVALUE, I have to change my implementation.

What I'm asking for is the equivalent of a pointer-pointer in the symbol
table, which I think could be valuable to extension writers.  Either
access to copy RVALUEs _or_ a reference struct, which could allow
me to use a VALUE as a pointer to another VALUE.  I have looked at
WeakRef, but it won't allow me to reassign the reference.  Plus, WeakRef
would throw off roundtripping of circular references.

  struct RRef {
    struct RBasic basic;
    VALUE ptr;
  }

In the extensions, you would pass around the VALUE to the RRef, but Ruby
would always call the RRef.ptr.  Similar to Delegator, WeakRef, but
simpler implementation.  Although this is a major change, especially for
those who serialize data.

I'd prefer it if I could copy an RVALUE.

_why