了解 PHP 元编程：动态代码操作

<?php

class dynamicclass {
    private $data = [];

    // magic method to handle dynamic property setting
    public function __set($name, $value) {
        echo "setting '$name' to '$value'.\n";
        $this->data[$name] = $value;
    }

    // magic method to handle dynamic property getting
    public function __get($name) {
        if (array_key_exists($name, $this->data)) {
            echo "getting '$name'.\n";
            return $this->data[$name];
        }

        echo "property '$name' not set.\n";
        return null;
    }

    // magic method to handle dynamic method calls
    public function __call($name, $arguments) {
        echo "calling method '$name' with arguments: " . implode(', ', $arguments) . "\n";
        return null;
    }
}

// usage example
$obj = new dynamicclass();

// setting properties dynamically
$obj->name = "metaprogramming";
$obj->type = "php";

// getting properties dynamically
echo $obj->name . "\n";  // outputs: metaprogramming
echo $obj->type . "\n";  // outputs: php

// calling a dynamic method
$obj->dynamicmethod("arg1", "arg2");

setting 'name' to 'metaprogramming'.
setting 'type' to 'php'.
getting 'name'.
metaprogramming
getting 'type'.
php
calling method 'dynamicmethod' with arguments: arg1, arg2

<?php

class exampleclass {
    public $name;
    public $type;

    public function __construct($name, $type) {
        $this->name = $name;
        $this->type = $type;
    }

    public function sayhello() {
        echo "hello from $this->name, a $this->type example!\n";
    }
}

function reflectonclass($classname) {
    // reflecting on the class
    $reflector = new reflectionclass($classname);

    echo "class: " . $reflector->getname() . "\n";

    // reflecting on the class properties
    echo "properties: \n";
    foreach ($reflector->getproperties() as $property) {
        echo "- " . $property->getname() . "\n";
    }

    // reflecting on the class methods
    echo "methods: \n";
    foreach ($reflector->getmethods() as $method) {
        echo "- " . $method->getname() . "\n";
    }
}

// usage example
$example = new exampleclass("metaprogramming", "php");
$example->sayhello();  // outputs: hello from metaprogramming, a php example!

// reflecting on the exampleclass
reflectonclass('exampleclass');

hello from metaprogramming, a php example!
class: exampleclass
properties: 
- name
- type
methods: 
- __construct
- sayhello

<?php

class calculator {
    public function add($a, $b) {
        return $a + $b;
    }

    public function multiply($a, $b) {
        return $a * $b;
    }
}

function dynamicinvoke($object, $methodname, $args) {
    try {
        $method = new reflectionmethod($object, $methodname);
        return $method->invokeargs($object, $args);
    } catch (reflectionexception $e) {
        echo "method not found: " . $e->getmessage() . "\n";
    }
}

// example usage
$calc = new calculator();

// dynamically invoke 'add' method
$result1 = dynamicinvoke($calc, 'add', [2, 3]);
echo "addition result: " . $result1 . "\n";  // outputs: 5

// dynamically invoke 'multiply' method
$result2 = dynamicinvoke($calc, 'multiply', [3, 4]);
echo "multiplication result: " . $result2 . "\n";  // outputs: 12

// attempt to invoke a non-existent method
dynamicinvoke($calc, 'subtract', [5, 2]);

Addition Result: 5
Multiplication Result: 12
Method not found: Method Calculator::subtract() does not exist