From: Gary Wright <gwtmp01@...>
Date: 2007-09-28T04:01:03+09:00
Subject: Re: Ruby's a = b vs PHP5's $obj1 =& $obj2


On Sep 27, 2007, at 10:34 AM, Jonas Roberto de Goes Filho (sysdebug)  
wrote:
>  PHP, $obj1 = & $obj2 means that both $obj1 and $obj2 points to the  
> same content. Its like hardlinks in Unix.
>
> In Ruby, depends of type of variable. If type of variable as  
> object, its work like as PHP. If type of variable as a number, its  
> not work as PHP.

There is no need to think of 'numbers' as a special case in Ruby.
And I don't think your example even illustrates that they are
different.

> sysdebug(main):031:0> num1 = 1         # num1 references the object  
> '1'
> => 1
> sysdebug(main):032:0> num2 = num1      # num2 references the object  
> '1'
> => 1
> sysdebug(main):033:0> num2
> => 1
> sysdebug(main):034:0> num1 = 2         # change num1 to reference  
> the object '2'
> => 2
> sysdebug(main):035:0> num2             # num2 still references the  
> object '1'
> => 1
> sysdebug(main):036:0>


The trick is to think of integer literals not as values but as
references to objects.  1 is not the "value" 1 but is a reference
to the Fixnum object that behaves like the number 1 and there is
only a single Fixnum object that behaves that way (i.e. Fixnum objects
are *not* containers for integer values).

Note: Not everyone thinks of Ruby integer's in this way but IMHO
it makes Ruby's assignment semantics very simple and regular.

Gary Wright