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Subject: Re: [PHP-DEV] Alias stdClass to DynamicObject?
From: rowan.collins@gmail.com (Rowan Tommins)

On 08/09/2021 16:37, Mike Schinkel wrote:

> All future code that needs to refer to the class name will still refer to `stdClass`, so we won't be gaining much by creating an alias.


Just to be clear, the only code that would need to change is code that 
dynamically gets *out* the class name, from get_class(), var_export(), 
reflection, and the like. Using the class name in code, like "$foo = new 
stdClass;" and "$foo instanceof stdClass", would carry on working just 
fine, whichever way we defined the alias.


> Besides, don't forget `stdClass::class` in addition to `get_class()`.


The ::class syntax is purely string replacement (apart from some rare 
edge cases), and works identically whether the class exists, is an 
alias, or doesn't exist at all.


> I assume we would also disallow dynamic properties in anonymous classes too, right? After all, they are just statically declared classes that the developer do not assign a name.


The difference I see is that stdClass/DynamicObject allows you to add or 
remove properties from an object *after it has been created*. I think a 
lot of use cases don't actually need that, and would benefit from error 
messages when doing so accidentally.

You mentioned short-hand syntaxes like this:

> $obj = {
>      foo: 1,
>      bar: "hello",
>      baz: true,
> };

I would love for that, or some other short-hand, to be equivalent to this:

$obj = new class(foo: 1, bar: "hello", baz: true) {
     public $foo;
     public $bar;
     public $baz;
     public function __construct($foo, $bar, $baz) {
        $this->foo  = $foo;
        $this->bar = $bar;
        $this->baz = $baz;
     }
}

That is, an anonymous class, with exactly those three properties. If you 
*also* want to be able to define extra properties after it's created, 
you could opt into that using whatever mechanism a named class would 
(parent class, trait, attribute, etc; see other thread).

Similarly, the objects created by json_decode or PDO_FETCH_OBJECT only 
need the *initial* properties to be dynamic, not to allow properties to 
be added later.


Regards,

-- 
Rowan Tommins
[IMSoP]