function Greeter(target: Function) {
    target.prototype.greet = function() {
        console.log('Hello from Greeter!');
    };
}

@Greeter
class MyClass {
    constructor() {}
}

const myClassInstance = new MyClass();
(myClassInstance as any).greet(); // Hello from Greeter!

function Log(target: any, propertyKey: string, descriptor: PropertyDescriptor) {
    const originalMethod = descriptor.value;
    descriptor.value = function (...args: any[]) {
        console.log(`Calling ${propertyKey} with arguments`, args);
        return originalMethod.apply(this, args);
    };
}

class Calculator {
    @Log
    add(a: number, b: number) {
        return a + b;
    }
}

const calculator = new Calculator();
calculator.add(2, 3); // Calling add with arguments [2, 3]

function Enumerable(value: boolean) {
    return function (target: any, propertyKey: string, descriptor: PropertyDescriptor) {
        descriptor.enumerable = value;
    };
}

class Person {
    private _name: string;

    constructor(name: string) {
        this._name = name;
    }

    @Enumerable(false)
    get name() {
        return this._name;
    }
}

const person = new Person('John');
console.log(person.name); // John

function ReadOnly(target: any, propertyKey: string) {
    const descriptor: PropertyDescriptor = {
        writable: false
    };
    Object.defineProperty(target, propertyKey, descriptor);
}

class Car {
    @ReadOnly
    brand: string;

    constructor(brand: string) {
        this.brand = brand;
    }
}

const car = new Car('Toyota');
car.brand = 'Honda'; // TypeError: Cannot assign to read only property 'brand' of object

function LogParameter(target: any, propertyKey: string, parameterIndex: number) {
    const existingParameters = Reflect.getOwnMetadata('log_parameters', target, propertyKey) || [];
    existingParameters.push(parameterIndex);
    Reflect.defineMetadata('log_parameters', existingParameters, target, propertyKey);
}

class Library {
    greet(@LogParameter message: string) {
        console.log(message);
    }
}

const library = new Library();
library.greet('Hello, Decorators!'); // Hello, Decorators!