你能在 PHP 的 function 中设置一个常量 class 属性吗？

Question

Sorry for the weird title wording.

I want a class to have a property that can be viewed but not changed, and I want to set it inside a function.

Like this:

class Foo {
    public int $bar;

    public function __construct(int $input) {
        if ($input < 4) {
            $this->bar = $input;
        }
    }
}

$foo = new Foo(2);
echo $foo->bar; // Returns 2
$foo->bar = 1   // Gives error

Answer 1

Yes, this is possible and a very common practice:

class Foo
{
    private $bar;

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

    public function __construct() {
        // set $bar according to some logic
    }
}