Hello Zeev,
though the idea is nice and & does what we want here to a certain level it
still doesn't allow to implement ifsetor() or coalesce() or any other flavor
described here as proved by the following snippet:
[EMAIL PROTECTED] ~ $ php -r 'function ifsetor(&$a, $def=false) { return
isset($a) ? $a : $def; } $a= array(); $x = ifsetor($a[12][34], 42);
var_dump($x); var_dump($a);'
int(42)
array(1) {
[12]=>
array(1) {
[34]=>
NULL
}
}
I expect $a to be untouched of course. May this is another reason to
implement my const pass signature info. But then it might not be
implementable for this specific problem.
best regards
marcus
Tuesday, June 14, 2005, 4:26:44 PM, you wrote:
> At 17:10 14/06/2005, Sven Fuchs wrote:
>> > This implementation of issetor() actually works fine, except it does
>> > pollute the symbol tables with empty variables ($a and $b in this
>> > examples are created, as nulls).
>>
>>What are the consequences of polluting the symbol tables this way?
> Well, it will increase memory usage, but unless you're dealing with a huge
> amount of variables, that should be pretty negligible. It might also not
> work properly in certain cases, because PHP isn't truly capable of
> differentiating between variables those empty variables and real variables
> that contain nulls. For example,
> function ifsetor(&$x) { }
> ifsetor($foo);
> print $foo;
> will not generate a notice on a non existing variable, but will emit it if
> the call to ifsetor() is removed.
>>Should this issetor() be considered a "bad practice", probably for
>>medium to large scale applications?
> I think that a more practical implementation may be something like:
> function ifsetor(&$x, $default=null)
> {
> if (!isset($x)) {
> $x = $default;
> }
> return $x;
> }
> i.e., assign the variable with the default value if it doesn't yet
> exist. I think it usually desirable (not always, naturally) and since we
> want the variable to exist in this case, there's no pollution issue.
> I fully agree with everyone else that wondered why we're discussing
> this. People can implement this on their own, the way they want it, with
> an assignment or without it, using empty() or isset(), etc.
> Zeev
--
Best regards,
Marcus mailto:[EMAIL PROTECTED]
--
PHP Internals - PHP Runtime Development Mailing List
To unsubscribe, visit: http://www.php.net/unsub.php
