Re: RFC proposal : "new" keyword shorthand

On Fri, Jun 7, 2024, at 5:56 PM, ericmann@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