Implement "Constructor Promotion"

[nikic]

RFC: https://wiki.php.net/rfc/constructor_promotion

As recently discussed on list, this implements the following short hand syntax:

class Point {
    public function __construct(
        public float $x = 0.0,
        public float $y = 0.0,
        public float $z = 0.0,
    ) {}
}

This desugars to:

class Point {
    public float $x;
    public float $y;
    public float $z;

    public function __construct(
        float $x = 0.0,
        float $y = 0.0,
        float $z = 0.0
    ) {
        $this->x = $x;
        $this->y = $y;
        $this->z = $z;
    }
}

[TysonAndre]

Could add a test of global functions/closures - I'd guess that the following snippet probably has a misleading error message (not sure what scope->properties_info is)

<?php
function __construct(public $x) {}

LGTM otherwise

[nikic]

Added a test in 717134e, error message seems fine. Or did you expect something different there?

[nikic]

Ah sorry, I missed that you had function __construct() in particular in mind here. Changed the name in 7139cdc.

Still works fine though, because is_ctor above includes a check that scope is not null.

[TysonAndre]

Oh, didn't see the scope part of the check

[enumag]

Somehow I'm more interested in the TODO: Allow comma here. 😛

[okdewit]

@nikic Is there a reason to not go a step further, and use a "Kotlin style" syntax?

class Point (
    public float $x = 0.0,
    public float $y = 0.0,
    public float $z = 0.0,
) {
    //
}

[TysonAndre]

inline_function:
...
	|	fn returns_ref '(' parameter_list ')' return_type backup_doc_comment T_DOUBLE_ARROW backup_fn_flags backup_lex_pos expr backup_fn_flags
			{ $$ = zend_ast_create_decl(ZEND_AST_ARROW_FUNC, $2 | $12, $1, $7,
				  zend_string_init("{closure}", sizeof("{closure}") - 1, 0), $4, NULL,
				  zend_ast_create(ZEND_AST_RETURN, $11), $6);
				  ((zend_ast_decl *) $$)->lex_pos = $10;
				  CG(extra_fn_flags) = $9; }

After this change, static arrow functions with parameters don't get the doc comments parsed properly in Reflection.

It should be easy to fix by changing fn returns_ref '(' parameter_list ')' return_type backup_doc_comment to fn returns_ref backup_doc_comment '(' parameter_list ')' return_type and renumbering $n, unless there's a reason not to.

An example of affected code: $c = /** doc comment */ static fn(?int... $args): array => $args;

[nikic]

@TysonAndre Nice catch! It should be fixed now.

[TomasVotruba]

In the RFC code example the trailing comma is allowed, but not here.

Which is correct?

[someniatko]

This is the subject of different RFC

[TomasVotruba]

Yes, here is PHP Wiki: https://wiki.php.net/rfc/trailing_comma_in_parameter_list

[FlorianSteenbuck]

Is there any reflection possibility for visibility ?

[nikic]

@FlorianSteenbuck The visibility should be accessible through ReflectionProperty as usual.

[FlorianSteenbuck]

@nikic ok: https://3v4l.org/JsbXT

<?php

class Point {
    public function __construct(
        public float $x,
        public float $y = 0.0,
        public float $z = 0.0,
    ) {}
}

foreach ((new ReflectionClass(Point::class))->getProperties() as $property) {
    var_dump($property->name);
}

string(1) "x"
string(1) "y"
string(1) "z"

[zlianon]

@nikic what is the reason for which it is not allowed to declare promoted property in an abstract constructor?

interface InstructionInterface
{
    /**
     * InstructionInterface constructor.
     *
     * @param mixed $operand
     */
    public function __construct(
        private mixed $operand,
    );

    /**
     * @param SplStack $stack
     */
    public function __invoke(SplStack $stack): void;
}

[nikic]

Promoted properties combine a property declaration with initialization of that property in the constructor. There is no way to initialize the property in an abstract constructor.

Your example is doubly illegal because it would also require declaring a property in an interface, which is not allowed.