Re: [PHP] PHP 4.3.11, call_user_func and instances of classes
On Wed, April 26, 2006 6:46 pm, David Otton wrote:
class Test {
var $x;
function Test ()
{
global $addition, $subtraction;
$this-x = 0;
$addition = array ($this, 'AddOne');
$subtraction = array ($this, 'SubtractOne');
Unsolicited Advice:
You MIGHT also want to consider using $this-addition and
$this-subtraction instead of global variables.
Just a bit cleaner, I think.
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[PHP] PHP 4.3.11, call_user_func and instances of classes
A bit of an oddity, this. There's some example code attached which
illustrates my problem.
I am attempting to call a method of an instance of an class from
outside that instance, using call_user_func().
What's happening is that my attempt to call
array ($this, 'AddOne')
is silently being rewritten into a call to
array ('Test', 'Addone')
in other words, instead of calling $test-AddOne I'm calling
Test::Addone. Thus, my expected output:
Add:1,Add:2,Add:3,Subtract:2,Subtract:1,Subtract:0,
becomes
Add:1,Add:1,Add:1,Subtract:-1,Subtract:-1,Subtract:-1,
So, my question is twofold:
a) How can I accomplish this?
b) Why is PHP silently modifying my code to mean something I didn't
write, rather than throwing up an error?
?php
$addition = $subtraction = null;
class Test {
var $x;
function Test ()
{
global $addition, $subtraction;
$this-x = 0;
$addition = array ($this, 'AddOne');
$subtraction = array ($this, 'SubtractOne');
doMath('+'); doMath('+'); doMath('+');
doMath('-'); doMath('-'); doMath('-');
}
function AddOne ()
{
$this-x++;
echo (Add:.$this-x.,);
}
function SubtractOne ()
{
$this-x--;
echo (Subtract:.$this-x.,);
}
}
function doMath($choice)
{
global $addition, $subtraction;
switch ($choice)
{
case '+':
call_user_func ($addition);
break;
case '-':
call_user_func ($subtraction);
break;
}
}
$test = new Test();
?
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Re: [PHP] PHP 4.3.11, call_user_func and instances of classes
The problem is not what it seems. PHP4 assigns object by copy, not by
reference. This is causing the call_user_func() to use a copy of the object
instead of the original object. So, all modifications are lost once the call
is done. One solution to this is to assign objects by reference:
$addition = array ($this, 'AddOne');
$subtraction = array ($this, 'SubtractOne');
2006/4/26, David Otton [EMAIL PROTECTED]:
A bit of an oddity, this. There's some example code attached which
illustrates my problem.
I am attempting to call a method of an instance of an class from
outside that instance, using call_user_func().
What's happening is that my attempt to call
array ($this, 'AddOne')
is silently being rewritten into a call to
array ('Test', 'Addone')
in other words, instead of calling $test-AddOne I'm calling
Test::Addone. Thus, my expected output:
Add:1,Add:2,Add:3,Subtract:2,Subtract:1,Subtract:0,
becomes
Add:1,Add:1,Add:1,Subtract:-1,Subtract:-1,Subtract:-1,
So, my question is twofold:
a) How can I accomplish this?
b) Why is PHP silently modifying my code to mean something I didn't
write, rather than throwing up an error?
?php
$addition = $subtraction = null;
class Test {
var $x;
function Test ()
{
global $addition, $subtraction;
$this-x = 0;
$addition = array ($this, 'AddOne');
$subtraction = array ($this, 'SubtractOne');
doMath('+'); doMath('+'); doMath('+');
doMath('-'); doMath('-'); doMath('-');
}
function AddOne ()
{
$this-x++;
echo (Add:.$this-x.,);
}
function SubtractOne ()
{
$this-x--;
echo (Subtract:.$this-x.,);
}
}
function doMath($choice)
{
global $addition, $subtraction;
switch ($choice)
{
case '+':
call_user_func ($addition);
break;
case '-':
call_user_func ($subtraction);
break;
}
}
$test = new Test();
?
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