Add limitation to php class

[html20009876]

This is C++ class format in php style:

class My
{
      var $name;
}

A variable must be defined before use in c++, i.e:
$my = new My();
$my->day ...

This causes a compile error in C++: $day is not defined in class My ...
But, php simply adds a variable $day to the class without any error.

This is really no good, may I add limitation to php class to simulate C++ class in case of example above?

Thanks.

.

[NogDog]

You can use the __set() "magic method" to limit what can be done.

<?php
class Test
{
    public $foo;
    private $bar;

    public function __set($varName, $value)
    {
        if( ! property_exists($this, $varName)) {
            throw new Exception("Invalid property '$varName'");
        }
        else {
            throw new Exception("Private property, keep off");
        }
    }
}

$test = new Test();
$test->foo = "This is okay";
try {
    $test->bar = "This should not be allowed.";
}
catch(Exception $e) {
    echo "<pre>".print_r($e, 1)."</pre>";
}
try {
    $test->fubar = "This won't work either.";
}
catch(Exception $e) {
    echo "<pre>".print_r($e, 1)."</pre>";
}

(You can use the __get() magic method to access non-public variables, too, which in combination with the __set() above could make them effective read-only.)

[html20009876]

Hi NogDog,

I never think there is a solution for my need.
Your code is over magic!

Does the checking function heavily slow down php execution?

Thanks a lot.

.

[NogDog]

I don't think the initial check to determine if the __set() method needs to be called at all should be slow, since that would be part of the underlying C code. If you actually get into the method itself, then you're in more or less "normal" PHP mode -- but since in this specific case we're throwing exceptions, ideally any developer would then adjust his/her client code to not do that. (sort of like a compilation error in C).