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Posted by Jochem Maas on 09/20/05 18:39
thanks everyone for the crash course in better understanding the underlying mechanisms!
.... I'm probably not the only one that learnt something from this ;-)
Dragan Stanojevic - Nevidljivi wrote:
> Jochem Maas wrote:
>
>>> Basically, in PHP, a reference (such as what key() takes as a
>>> parameter [1]) can only point to an actual variable, not directly to
>>> the result of a function. So you have to assign the output of the
>>> function to a variable first.
>>
>> wtf, Im now officially confused (before I suffered unofficially :-)
>>
>> if foo() expects one args by reference then why is doing:
>>
>> foo($a = 5);
>>
>> ..wrong? I always thought that the expression (in this form) 'returns'
>> the variable? or does it need to be:?
>>
>> foo( ($a = 5) );
>
>
> Well think like this: expression != variable != value :]
>
> Let me explain... most functions (and expressions!) return value, not
> variable (unless it's passed by reference). Usually, although most
> beginners don't know it, you ignore that value.
>
> For example, you could do:
>
> fopen( $filename, $filemode );
>
> and in that case return value (not variable) of fopen is ignored. This
> is a bad practice because you need to check it, but this is just an
> example. Most other functions return values that we ignore.
>
> Another example (not functions but expressions) is assigning a value:
>
> $a = 5; // returns 5 (and we ignore it again)
>
> it allows us to do the following:
>
> $a = $b = $c = 10;
>
> read from right to left, and it'll go something like this: "assign 10 to
> $c (it evaluates to 10), assign (previously assigned value) 10 to $b,
> and so on...".
>
> So in essence: $c = 5 in expression and returns the value of 5 not a
> variable/reference which can be changed.
>
> Hope this will help you a little,
> N::
>
> P.S. Just a thought... If you declare the method to return a ref maybe
> you can get away with it...
>
> private public & getThis() {
> $tempArr = array( 'a', 'b', 'c' );
>
> return $tempArr;
> }
>
> as opposed to:
>
> private public getThis() { ... }
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