| Re: Globalizing vars in class methods doesnt seem to work, var disappears after global, var is inaccessible in other methods/funcs [message #178795 is a reply to message #178794] |
Sun, 05 August 2012 04:08   |
J. Frank Parnell
Messages: 12
Registered: January 2012
Karma:
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Junior Member |
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On Saturday, August 4, 2012 11:45:35 AM UTC-7, Jerry Stuckle wrote:
> On 8/4/2012 2:24 PM, Jerry Stuckle wrote:
>
>> On 8/3/2012 1:45 PM, J. Frank Parnell wrote:
>
>>> <?php
>
>>> class test{
>
>>> function __construct(){
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>>> $this->makevar();
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>>> global $var;
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>>> echo '<hr>__const(): '.$var;
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>>> }
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>>> function makevar(){
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>>> $var = 'something';
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>>> echo '<hr>just declared in makevar(): '.$var;
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>>> global $var;
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>>> echo '<hr>after global in makevar(): '.$var;
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>>> }
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>>> }//class
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>>>
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>>> $t = new test;
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>>> echo '<hr>outside class: '.$var;
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>>> global $var;
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>>> echo '<hr>outside class after global: '.$var;
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>>>
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>>> ?>
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>>> this outputs:
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>>> just declared in makevar(): something
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>>> after global in makevar(): [nothing]
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>>> __const():[nothing]
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>>> outside class: [nothing]
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>>> outside class after global: [nothing]
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>>>
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>>>
>
>>> So, 1, why does global $var in the makevar() make it null?
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>>> and B, why dont I have any access to $var in the __constructor or
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>>> outside the class?
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>>>
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>>> In the real script, $var will be an instance of a different class that
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>>> I want to use all over the place.
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>>> thanks, J
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>>>
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>>
>
>> And what if you have:
>
>>
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>> $t1 = new test;
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>> $t2 = new test;
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>>
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>> Which variable are you supposed to be referencing (they are two
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>> different variables)?
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>>
>
>> But what you're doing violates several concepts in OO programming,
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>> including encapsulation and message passing. The correct way to do it
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>> is to pass an object of the class as a parameter (i.e. to the
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>> constructor) then use getters and setters to reference the variable.
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>> Proper coding makes your code more reliable, maintainable, reusable and
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>> easier to understand.
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>>
>
>
>
> An addition option I forgot to mention - you could also use the
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> singleton pattern as M. Strobel referenced. However, if you do, you
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> should always have a default parameter in the call so you can use
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> something other than the singleton when you need to.
Ok, I read a little on the singleton, that does seem like a good way of doing it. What I wound up doing, before you guys replied, was just $this->var = 'something' and then doing $t->var where I needed that 'something'. Which I think make sense for OO? Because it is somewhat logical for 'something' to be part of my class, in my situation. Although 'something' is a different object, eg, an api class. My class is a child class of a controller in an MVCish framework.
I just found out that this works
class test{
function __construct(){
$this->makevar();
}
function makevar(){
global $var;
$var = 'something';// actually, $var = new something();
}
}//class
$t = new test;
echo '<hr>outside class: '.$var;//works And I assume would work in a unrelated function if I globalled it in there.
> always have a default parameter in the call so you can use
> something other than the singleton when you need to
not sure what this means
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