PHP 4.0 Bug #7598 Updated: modify "new" syntax
| From: | sniper@php.net | Date: | Tue, 21 Nov 2000 09:01:37 +0000 |
| Subject: | PHP 4.0 Bug #7598 Updated: modify "new" syntax | ||
| Groups: | php.dev | ||
| Request: | Send a blank email to php-dev+get-38763@lists.php.net to get a copy of this message | ||
ID: 7598
Updated by: sniper
Reported By: danjrod@terra.es
Status: Open
Bug Type: Feature/Change Request
Assigned To:
Comments:
Previous Comments:
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[2000-11-02 15:39:53] danjrod@terra.es
With a simple script like the one below ....
Having a look at zend-parser.y also gives an insight into the problem. I can provide an adequate
patch for both of the alternatives I proposed in the "feature/change" request.
Hope this helps. I am typing the script in my portable, and
thus it may contain a typo - I have checked twice before submitting :-) - but I hope it
doesn't.
Regards
Daniel
---- script ----
class t1_t {
var $value;
function t1_t( &$p, $value) {
$this->value = $value;
$p->add( $this);
}
function output() {
echo "<br>" . $this->value;
}
}
class t_t {
var $child;
function t_t() {
}
function add( &$child) {
$this->child = &$child;
}
function output() {
$this->child->output();
}
}
$t = new t_t();
$t1 = new t1_t( $t, 5);
$t1->value = 8;
$t->output();
// output should be
// <br>8
// but the real output is
// <br>5
// since $t has stored the object during construction
// and $t1 the copy instead of the reference.
---------------------------------------------------------------------------
[2000-11-02 15:12:56] danjrod@terra.es
With a simple script like the one below ....
Having a look at zend-parser.y also gives an insight into the problem. I can provide an adequate
patch for both of the alternatives I proposed in the "feature/change" request.
Hope this helps. I am typing the script in my portable, and
thus it may contain a typo - I have checked twice before submitting :-) - but I hope it
doesn't.
Regards
Daniel
---- script ----
class t1_t {
var $value;
function t1_t( &$p, $value) {
$this->value = $value;
$p->add( $this);
}
function output() {
echo "<br>" . $this->value;
}
}
class t_t {
var $child;
function t_t() {
}
function add( &$child) {
$this->child = &$child;
}
function output() {
$this->child->output();
}
}
$t = new t_t();
$t1 = new t1_t( $t, 5);
$t1->value = 8;
$t->output();
// output should be
// <br>8
// but the real output is
// <br>5
// since $t has stored the object during construction
// and $t1 the copy instead of the reference.
---------------------------------------------------------------------------
[2000-11-02 14:15:57] waldschrott@php.net
how did you verify/find out that it is copied?
---------------------------------------------------------------------------
[2000-11-02 13:59:11] danjrod@terra.es
Assigning the value returned by "new xxxx()" to a variable creates a copy of the
constructed object.
"new" does not support returning references by default, or prepending an ampersand,
'&', to have a reference returned.
Thus the request is:
- Modify new syntax to either:
a) It always returns a reference. This is unlikely to
break any existing code. At most people will be
creating a reference to a reference, which won´t harm
b) Support the '&' syntax like in "&new xxx", so that
a reference can be asked for. This will not break
any existing code.
This only implies slightly modifying "zend-parser.y", and
no further changes to any part of the zend engine.
This change will cure the use of "$this" as a reference inside the object constructor,
which has been wrongly dismissed as a "circular reference problem".
Regards
Daniel
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Full Bug description available at: http://bugs.php.net/?id=7598