Associative mode for ReflectionAttribute::getArguments

[divinity76]

Description

Would be nice if ReflectionAttribute::getArguments had an associative mode, for example

<?php

#[Attribute(Attribute::TARGET_PARAMETER)]
class ArgumentDescription {
    public function __construct(
        public string $description,
        public mixed $example = null
    ) {}
}

function test(
    #[ArgumentDescription("amount in USD", 9.99)]
    float $amount,
) {}
$ref = new ReflectionFunction(test(...));
$parameter = $ref->getParameters()[0];
$parameterAttribute = $parameter->getAttributes()[0];
var_dump($parameterAttribute->getArguments());
var_dump($parameterAttribute->getArguments(associative: true));

could print

array(2) {
  [0]=>
  string(13) "amount in USD"
  [1]=>
  float(9.99)
}
array(2) {
  ["description"]=>
  string(13) "amount in USD"
  ["example"]=>
  float(9.99)
}

[DanielEScherzer]

@divinity76 we already use an associative array for any arguments that are specified as named arguments:

<?php

#[Attribute(Attribute::TARGET_PARAMETER)]
class ArgumentDescription {
    public function __construct(
        public string $description,
        public mixed $example = null
    ) {}
}

function test(
    #[ArgumentDescription(description: "amount in USD", example: 9.99)]
    float $amount,
) {}
$ref = new ReflectionFunction(test(...));
$parameter = $ref->getParameters()[0];
$parameterAttribute = $parameter->getAttributes()[0];
var_dump($parameterAttribute->getArguments());

returns

array(2) {
  ["description"]=>
  string(13) "amount in USD"
  ["example"]=>
  float(9.99)
}

does that meet your use case? Or do you want to try and associate positional parameters with the underlying name?
Since ReflectionAttribute (and getArguments()) work without requiring that the underlying attribute class exist, switching to fetching the positional parameter names would require checking the parameters in the class constructor.

[divinity76]

@DanielEScherzer Neat! but no, i am not perfectly happy with it.
What I am perfectly happy with, is the output of

<?php

#[Attribute(Attribute::TARGET_PARAMETER)]
class ArgumentDescription {
    public function __construct(
        public string $description,
        public mixed $example = null
    ) {}
}

function test(
    #[ArgumentDescription("amount in USD", 9.99)]
    float $amount,
) {}
$ref = new ReflectionFunction(test(...));
$parameters = $ref->getParameters();
$parameter = $parameters[0];
$parameterAttributes = $parameter->getAttributes();
$parameterAttribute = $parameterAttributes[0];
$paramteterAttributeArguments = $parameterAttribute->getArguments();
var_dump($parameterAttribute->getArguments());
// associative code starts here:
$instance = $parameterAttribute->newInstance();
$constructor = (new \ReflectionObject($instance))->getConstructor();
$constructorParameters = $constructor->getParameters();
$associative = [];
foreach($paramteterAttributeArguments as $argumentIndex => $argumentValue) {
    $argumentName = $constructorParameters[$argumentIndex]->getName();
    $associative[$argumentName] = $argumentValue;
}
var_dump($associative);

which does output

array(2) {
  [0]=>
  string(13) "amount in USD"
  [1]=>
  float(9.99)
}
array(2) {
  ["description"]=>
  string(13) "amount in USD"
  ["example"]=>
  float(9.99)
}

I still think it would be nice if php natively supported it with a much simpler

var_dump($parameterAttribute->getArguments());
// associative code starts here:
var_dump($parameterAttribute->getArguments(associative: true));

, but nice to know it's already doable in userspace

[divinity76]

Hmm maybe some day,
but I think the PHP project has better things to focus on.
Closing.

[DanielEScherzer]

@DanielEScherzer Neat! but no, i am not perfectly happy with it. What I am perfectly happy with, is the output of

I still think it would be nice if php natively supported it with a much simpler

var_dump($parameterAttribute->getArguments(associative: true));

, but nice to know it's already doable in userspace

I think this would need some other method name, since

• that parameter would suggest that it is unassociative if the value is false (but it is already associative, just limited to named parameters)
• the method would trigger some extra behavior of loading the class, and so can have different error conditions (getArguments() is safe to use even if the actual attribute class doesn't exist, convertToNamedArguments() (or whatever it is called) would not be safe to use in that case)

This probably needs an RFC, or at least a discussion on the mailing list

In the meantime, the following might be simpler.

$ass = array_combine(
    array_map(
        static fn ( $r ) => $r->getName(),
        (new ReflectionClass( $parameterAttribute->getName() ) )->getConstructor()->getParameters()
    ),
    $parameterAttribute->getArguments()
);
var_dump($ass);

[divinity76]

that parameter would suggest that it is unassociative if the value is false (but it is already associative, just limited to named parameters)

good point. I do find that limitation, being limited to only associative on named parameters, to be strange.
Do you know the rationale behind it?

the method would trigger some extra behavior of loading the class,

I don't think a php-internal implementation would actually need to do that.

the following might be simpler

Neat, thanks!

Also I think it's a good thing that the next person looking assosative ReflectionAttribute::getArguments
can find this thread on GH.

[DanielEScherzer]

that parameter would suggest that it is unassociative if the value is false (but it is already associative, just limited to named parameters)

good point. I do find that limitation, being limited to only associative on named parameters, to be strange. Do you know the rationale behind it?

Presumably so that the actual class doesn't need to be looked up