Re: [Yaml-core] Reference Problems

[Clark C . E. <cc...@cl...>]

On Sat, Nov 10, 2001 at 07:55:14PM -0800, Brian Ingerson wrote:
| Perl does not need two different kinds of references.

Ok.  I'm not a perl head, so take it easy on me.

  $a = [0]
  $b = $a
  $c = \$a

How do $b and $c differ? 

  $b->[0] = 9
  print $a->[0]

Prints out "9".  So, somehow, someway, $b is
an alias for the array also pointed to by $a.
This is the *alias* mechanism, and Perl seems
to have it.  This is what &001 and *001 were
design to encode. The first time an object is 
encountered it is serized and given an anchor,
then on subsequent appearences, we use *001.
Right?  Let's call this an "alias".  And an 
"alias" is not what I have with $c above... no?

Thus, we need another mechanism.  An explicit
map having the type !ptr works just great.  As 
it says on P245 of camel book at the bottom:
"[the \ mechanism] works much like the & 
  operator in C".  Thus, I'm calling the
"reference" in Perl a pointer.  Java and Python
don't have pointers... Perl does.

That's all.  Right?  So we need a pointer 
mechanism (or type).  But I don't think that
pointers need be at all related to our alias
mechanism.  The map syntax that Oren started
and I tried to explain will allow round-tripping
pointers through any YAML system without 
pointers... as it is stored as a map with a
particular type.  Kinda cool, if you ask me.

Clark