doubling the -> operator

[sguazt]

Hi,
I'm learning PHP so sorry if this question might be trivial :-P
Suppose you have an object Foo which has a property of object Bar (i.e. whose "type" is the object Bar) which in turn has a property of another object Bazz.
So I thought I could write:
$foo =& new Foo();
...
$bazz = $foo->getBar()->getBazz();

but I got a Parse Error.
So really in PHP you couldn't do that?!?!
Am I forced to use a temporary variable:
$bar = $foo->getBar();
$bazz = $bar->getBazz();
?

Thanks in advance!!

[laserlight]

A simple question: can a method have a method?

Also, what does the getBar() method do?

[sguazt]

I've missed to specify what version of PHP I use!! 😛

RPM php-4.3.4-1.1 for Fedora Core 1 (i386)

[sguazt]

Originally posted by laserlight
A simple question: can a method have a method?

Also, what does the getBar() method do?

class Foo
{
var $_bar;

...

function getBar()
{
    return $this->_bar;
}

}

class Bar
{
var $bazz;
...
function getBazz()
{
return $this->bazz;
}

function speak() { .... }
}

class Bazz
{
...
function sing() { .... }
}

...
$foo = new Foo();
....
$foo->setBar( $aBar );
...
$foo->getBar()->speak();

or even:
$foo->getBar()->getBazz()->sing();

usually in java, cpp you can do that 😉

[laserlight]

I dont have the facility on this comp to test PHP code, but what if...

<?php
class Foo {
	var $bar;
	function Foo() {
		$this->bar = new Bar;
	}
	function getBar() {
		return $this->bar;
	}
}

class Bar {
	var $baz;
	function Bar() {
		$this->baz = new Baz;
	}
	function getBaz() {
		return $this->baz;
	}
}

class Baz {
	var $foobar;
	function Baz() {
		$this->foobar = 1;
	}
	function getFooBar() {
		return $foobar;
	}
}

$foo = new Foo;
$bazz = ${$foo->getBar()}->getBaz();
echo $bazz->getFooBar();
?>

with the idea of using variable variables.

Never tried anything like this though, since generally a temporary variable will suffice.

[sguazt]

Originally posted by laserlight
I dont have the facility on this comp to test PHP code, but what if...

<?php
//...
?>

with the idea of using variable variables.

Never tried anything like this though, since generally a temporary variable will suffice. [/B]

I've just tried your idea but don't work:
<b>Fatal error</b>: Call to a member function on a non-object in ... on line 33

So I've tried to write a test case

<?php
class Foo
{
        var $_bar;

    function Foo()
    {
    }

    function setBar( $bar )
    {
            $this->_bar = $bar;
    }

    function getBar()
    {
            return $this->_baz;
    }
}

class Bar
{       

        var $_baz;

    function Bar()
    {
    }

    function setBaz( $baz )
    {
            $this->_baz = $baz;
    }

    function getBaz()
    {
            return $this->_baz;
    }

}

class Baz
{
        var $_song;

    function Baz( $song )
    {
            $this->_song = $song;
    }

    function sing()
    {
            print $this->_song . "\n";
    }
}

$bar = new Bar();
$bar->setBaz( new Baz( 'Voodoo Child' ) );
$foo = new Foo();
$foo->setBar( $bar );

${$bar->getBaz()}->sing();      //don't work
//${${$foo->getBar()}->getBaz()}->sing();       //don't work too

?>

also this code gave the same error. 🙁
Ya temp vars work ... but sometimes are annoying 8)

[sguazt]

I've also tried with:

<?php
{$baz->getBaz()}->sing()
?>

and with:

<?php
($baz->getBaz())->sing()
?>

but nothing :/

[mrhappiness]

won't work with pp < 5.x

don't know how it will be when php 5 is really released

[swr]

I've seen some mention that this will work with PHP 5, although I don't have a PHP 5 install to confirm it.

[Weedpacket]

Originally posted by swr
I've seen some mention that this will work with PHP 5, although I don't have a PHP 5 install to confirm it.

I'll confirm that PHP5 does do dereferencing, so that "$foo->bar()->baz()" works so long as "$foo->bar()" returns an object with a baz() method), but PHP4 doesn't, meaning workarounds like

$temp = $foo->bar();
$temp->baz();

are necessary in that version.