La clase ReflectionFunction

We can use this functionality to automatically pass arguments to our function based on some data structure.

NOTE: I am using a php 8.0> feature called "Nameds parameter"

<?php

$valuesToProcess = [
  'name' => 'Anderson Lucas Silva de Oliveira',
  'age' => 21,
  'hobbie' => 'Play games'
];

function processUserData($name, $age, $job = "", $hobbie = "")
{
    $msg = "Hello $name. You have $age years old";
    if (!empty($job)) {
    $msg .= ". Your job is $job";
    }

    if (!empty($hobbie)) {
        $msg .= ". Your hobbie is $hobbie";
    }

    echo $msg . ".";
}

$refFunction = new ReflectionFunction('processUserData');
$parameters = $refFunction->getParameters();

$validParameters = [];
foreach ($parameters as $parameter) {
    if (!array_key_exists($parameter->getName(), $valuesToProcess) && !$parameter->isOptional()) {
        throw new DomainException('Cannot resolve the parameter' . $parameter->getName());
    }

    if(!array_key_exists($parameter->getName(), $valuesToProcess)) {
        continue;
    }

    $validParameters[$parameter->getName()] = $valuesToProcess[$parameter->getName()];
}

$refFunction->invoke(...$validParameters);
?>

Results in:

Hello Anderson Lucas Silva de Oliveira. You have 21 years old. Your hobbie is Play games.

Here is a concise example of ReflectionFunction usage for Parameter Reflection / introspection (e.g. to automatically generate API descriptions)

<?php
$properties = $reflector->getProperties();
$refFunc = new ReflectionFunction('preg_replace');
foreach( $refFunc->getParameters() as $param ){
    //invokes ■ReflectionParameter::__toString
    print $param;
}
?>

prints:

Parameter #0 [ <required> $regex ]
Parameter #1 [ <required> $replace ]
Parameter #2 [ <required> $subject ]
Parameter #3 [ <optional> $limit ]
Parameter #4 [ <optional> &$count ]