php use object property value as variable variable name

Question

I'm trying to make a wrapper class for the primitive types in php but I encountered a problem while making a 'string' class;

If a create a new class like $str = new _string(); it would be nice if i could still assign the value with $str = 'foo'; but of course that will overwrite $str and the class will be destroyed.

So I had the (possibly crazy) idea of accessing the class with $str and its value with $$str by creating $$str in the global scope when instantiating $str

The problem is global $$this->name doesn't work as I'd expect, infact I'm not quite sure whats going on.

class _string {

    private $name;

    public function __construct($name) {
        $this->name = 'str_' . $name;     
        global $$this->name;         // <---this doesn't work properly   
        $strName = 'str_' . $name;        //assigning a global variable variable
        global $$strName;                 //from a local variable works fine   
    }

    public function __toString() {
        return $this->name;
    }

    public function rev() {
        $strName = $this->name;
        global $$strName;
        $$strName=strrev($$strName);
        $$this->name=strrev($$this->name);
    }                         //       ^
                              //       |
}                             //       |
                              //       |
$str = new _string('str');    //       |
$$str = 'hello';              //       |
$str->rev();    //Warning: Attempt to assign property of non-object 
echo $$str;     //olleh

My aim is to avoid using $str->value='foo' and get as close to $str='foo' as possible

Is this even possible? Or does anyone have a better suggestion?

TL;DR but I think you have some missing brackets: $$this->name -- ${$this->name} — Álvaro González
– Álvaro González, Commented May 8, 2014 at 16:27
You're aiming to treat a string primitive like an object with methods? — Michael Berkowski
– Michael Berkowski, Commented May 8, 2014 at 16:28
Nikic has a good recent post about this in the future of PHP... (not that it solves what you're trying to do here) — Michael Berkowski
– Michael Berkowski, Commented May 8, 2014 at 16:30
@MichaelBerkowski so in essence the aim is to get as close to $str = new _string(), $str ='foo';,$str->rev();, echo $str // oof as possible — andrew
– andrew, Commented May 8, 2014 at 16:31

Álvaro González · Accepted Answer · 2014-05-08 16:48:19Z

2

This:

$$a->b

... means:

Take variable $a
Cast to string
Use the string to call the variable with that name
Read property b

Since $a (in your case $this) is an object, it feels like a bug. You possibly want:

${$this->name}

answered May 8, 2014 at 16:48

Álvaro González

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