On Fri, Jun 7, 2024, at 5:56 PM, ericm...@php.net wrote:
>> Instead of ~ (which reminds me of the pendulum of symbols to written to
>> symbols and back again every 10ish years; “or” vs “||”), why not make a
>> shorthand way to write a function that calls a constructor (kinda sorta like
>> C# extension methods)? Something kinda like:
>>
>> class MyClass implements Invocable {
>> public function __construct($i) {}
>> }
>>
>> MyClass($i);
>>
>> Where the Invocable interface defines a function of the same class name in
>> the namespace that is an alias for a new objects and forwards args to the
>> constructor. This could be quite handy for value objects.
>>
>> I’m not necessarily a fan of magic or symbols, but just tossing it out there
>> to spark ideas.
>>
>> — Rob
> --
>
> I'm not a fan of using ~ for this shorthand, due to the same issues
> that have been brought up elsewhere (i.e. it already has meaning). But
> the idea of a new interface auto-defining a function of the same name
> is attractive. It's something I've done manually to mirror code in PHP
> from other implementations existing in Scala leveraging case classes.
>
> https://docs.scala-lang.org/tour/case-classes.html for anyone
> unfamiliar with the construct:
>
> ```
> case class Book(isbn: String)
>
> val frankenstein = Book("978-0486282114")
> ```
>
> Doing something like this in PHP is a bit more ... verbose today:
>
> ```
> class Book
> {
> public function __construct(public string $isbn) {}
> }
>
> function Book(string $isbn): Book
> {
> return new Book($isbn);
> }
>
> $frankenstein = Book("978-0486282114")
> ```
>
> That's a lot of boilerplate for the shorthand to not require a `new`
> keyword. Which is to say, I both agree in principle with the RFC and
> think this would add value (particularly if I could extend the default
> behavior of this kind of interface to support immutability, comparison,
> etc similar to Scala case classes). I'm just not a fan of the current ~
> proposal.
>
> ~Eric
The issue with auto-generating a function constructor for a class is that we
still don't have function autoloading. Which means this:
// Point.php
#[MakeFactoryFunction] (or whatever)
class Point {
public function __construct(public int $x, public int $y) {}
}
// index.php
$p = Point(4, 5);
will look for a function named "Point", not find one defined yet, and fatal.
If we had function autoloading, that would work, assuming a reasonable generic
autoloader for that case could be written. Who was it that's been talking
about that for a while? :-)
Or if we had some marker to indicate "this function call is a wrapper for a
class so autoload it like a class", that could then trigger the class
autoloader. But... that's basically what the original ~ proposal is, in the
end. Though I agree that ~ is not a great symbol for it. PHP has, sadly, run
out of unused symbols. (I've run into this a couple of times now.)
--Larry Garfield
