ID: 9477
Updated by: jmoore
Reported By: [EMAIL PROTECTED]
Status: Open
Old-Bug Type: Scripting Engine problem
Bug Type: Documentation problem
PHP Version: 4.0.4pl1
Assigned To:
Comments:
Docu problem not script engine problem.
- James
Previous Comments:
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[2001-03-09 01:54:31] [EMAIL PROTECTED]
Ok. This is absolutely amazing. I went to the archives. There are a good number of
people all wondering about the same issue. Why is =&new required when every other
language semantically understands that new is an operator and =new is not an
assignment but rather implicit construction of an object?
Any takers?
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[2001-03-09 01:28:37] [EMAIL PROTECTED]
this all makes sense and generally you do NOT need to use
"=& new" your case included, this is due to PHPs nature and
this all has been discussed
search the archives (marc.theaimsgroup.com) for
"reference counting" and "this+constructor" or maybe "=&" to
understand when it required to use "=&" with new
there are some resources on reference counting in the manual
or at zend.com IRC
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[2001-03-09 00:32:08] [EMAIL PROTECTED]
I retract this bug. I think the issue is that I was looking for pointer semantics in a
language that does not support it but at the same time is not strongly typed so that
what appears to be correct, does not in fact reset the reference but actually
overwrites the original object by assignment.
Thank you all for your help. I now have a proper reference implementation of the
subscriber/publisher pattern for PHP.
Hopefully, I'll be able to keep this all straight for any other patterns I conver to
PHP.
Just out of curiosity, has ANYONE questioned the whole =& new construct's necessity in
terms of why the semantics allows for = new as well??? When would you want to assign
the a copy of the object you just created?
Any help would be appreciated.
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[2001-03-08 20:55:49] [EMAIL PROTECTED]
bogusifying
apparently you do not know what you are doing here exactly,
please read "references explained" from the manual again...
/* your version - you do not destroy the reference, you
simply overwritte all referenced variables (remember they
are all ONE variable know) with "" */
function junk($name){$this->array[$name]="";}
/* corrected version - this one does what it is written in
your description */
function junk($name){unset($this->array[$name]);}
the corrected one works for me.
/* to clear things up a bit - the following code does the
following: remove the reference by replacing it with another
(to $t), I could imagine you thought it does something
different */
function nojunk($name){$t="";$this->array[$name]=&$t;}
please note I still did not read your comments, your code
reduced code was enough to understand the situation completely
note: please do not use pass-by-ref in call time
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[2001-03-08 20:07:23] [EMAIL PROTECTED]
I'm really getting tired of this. I guess what I REALLY needed to do is strip out the
do nothing functions in the skeletons I had on that page because even though they were
base classes, everyone was missing the point.
Here is the simplest case that generates an error. Anyone want to take a stab at why
it happens?
<?php
class obj {
var $array;
// Assigns object reference to the associative array
function test($name,$obj){$this->array[$name]=&$obj;}
// Removes the reference from the associative, supposedly
// but what it does decrease the actual object to nothing
function junk($name){$this->array[$name]="";}
// If I do it this way it works. The object isn't nuked.
// What gives? Do I *HAVE* to use =&$ when assigning refs?
// Is there an array function that can be used to simply
// remove the array element out, w/o expensive copying?
function nojunk($name){$t="";$this->array[$name]=&$t;}
};
// Our do nothing class.
class me{
function test(){echo "Hello, I'm still validn";}
};
// Please don't tell me not to send the reference to the
// object because I need to have only one copy of the object
// and not a million of them especially since these objects
// might be opening files and sockets.
$m=& new me();
$o=& new obj();
// This section works
$o->test("test",&$m);
$m->test();
$o->nojunk("test");
$m->test();
// This section fails....
$o->test("test",&$m);
$m->test();
$o->junk("test");
// Right here
$m->test();
?>
So? What's the deal? Once you assign a reference to a variable, you're done? You can't
ever reassign the reference? Does what I'm proposing make sense syntactically
speaking? I want the array to contain the reference to the object, but then I want to
be able to unassign the reference from the array so that that particular object
doesn't get used. An unregistration as it were.
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comments, please view the bug report online.
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