I've been having some problems with a parse error that I can't figure
out (PHP 4.3.11 on Solaris9). Sample code:

<?php
// getting strange parse errors on this
class A {
var $value;
function A() {
$this->value = 1;
}

function getValue() {
return $this->value;
}
}

$a = new A();
if (!empty($a->getValue())) {
echo "success";
}
else {
echo "failure";
}
?>

The result of this is:

Parse error: parse error, unexpected '(', expecting ')' in
/foo/public_html/parse_errors.php on line 15

I also get the same effect with "isset", however, testing with "is_null"
or "is_int" produces the correct ("success"/"failure") result. Any ideas?

/Marcin

Check out the following:

http://www.php.net/manual/en/function.empty.php

empty() and isset() only work on variables. In your case,
$a->getValue() is the return value of a function -- not a variable.
You could do something like:

$a = new A();
$v = $a->getValue();
if (!empty($v)) {
echo "success";
}
else {
echo "failure";
}

Alternatively, you could define your own isEmpty() function which does
whatever you want. It could be as simple as:

function isEmpty($value) {
return (strlen($value) == 0);
}

Also, as of PHP 5.1 you can overload calls to empty() and isset() on
object properties. Most useful when you also overload the getters and
settings (via __get() and __set()).

ZeldorBlat wrote:[color=blue]
> Check out the following:
>
> http://www.php.net/manual/en/function.empty.php
>
> empty() and isset() only work on variables. In your case,
> $a->getValue() is the return value of a function -- not a variable.
> You could do something like:[/color]

Yea, thanks. I noticed this just as I posted the article, and then
promply canceled it, but it seems it didn't get canceled everywhere.
the is_int and is_null work differently, and it threw me off a bit.
[color=blue]
> $a = new A();
> $v = $a->getValue();
> if (!empty($v)) {
> echo "success";
> }
> else {
> echo "failure";
> }[/color]

Yes, that's how I do it now. A bit of fuss, but works.
[color=blue]
> Alternatively, you could define your own isEmpty() function which does
> whatever you want. It could be as simple as:
>
> function isEmpty($value) {
> return (strlen($value) == 0);
> }[/color]

Yes, but again, "empty" checks for null, 0, etc. Which is useful.
[color=blue]
> Also, as of PHP 5.1 you can overload calls to empty() and isset() on
> object properties. Most useful when you also overload the getters and
> settings (via __get() and __set()).[/color]

Will have a lookie, but still working in 4.x level (and it's not
going to change anytime soon). Thanks.

/Marcin

Well, that's the beauty of writing your own isEmpty()...you can have it
do whatever you want. You could simulate PHP's empty() behavior pretty
easily:

function isEmpty($value) {
return (strlen($value) == 0 || is_null($value) || $value == 0);
}

Hello!
[color=blue]
> Well, that's the beauty of writing your own isEmpty()...you can have it
> do whatever you want. You could simulate PHP's empty() behavior pretty
> easily:
>
> function isEmpty($value) {
> return (strlen($value) == 0 || is_null($value) || $value == 0);
> }[/color]

If you want to emulate PHP empty()'s behaviour completely (and only
then) you should use

function isEmpty($value) {
return empty($value);
}

I assume this is faster than doing the checks yourself.

Greetings,
Hero