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Can you explain the concept of generator delegation in PHP?

Hey everyone,

I have been working with generators in PHP recently and came across the term "generator delegation." I tried to read about it, but I'm still a bit confused. Can someone please explain to me what generator delegation is in PHP?

I understand the concept of generators and how they work, but I'm not sure how delegation fits into the picture. I would really appreciate it if someone could shed some light on this topic and provide an example or two to help me understand better.

Thanks in advance!

All Replies


Hey there!

Generator delegation in PHP is a pretty handy concept that allows you to simplify your code when working with multiple generators. It helps you avoid nested loops and unnecessary complexity.

To put it simply, generator delegation allows one generator to yield values from another generator. Instead of manually iterating over the second generator and passing the values to the first generator, you can use the `yield from` keyword to delegate the responsibility to the second generator.

Let me give you an example to make it clearer. Say we have two generators, `generatorA` and `generatorB`. We want to iterate through both generators and yield their values combined.

function generatorA() {
yield 'A1';
yield 'A2';

function generatorB() {
yield 'B1';
yield 'B2';

function generatorAB() {
yield from generatorA();
yield from generatorB();

foreach (generatorAB() as $value) {
echo $value . ' ';

// Output: A1 A2 B1 B2

In the above example, when `generatorAB` is called, it delegates the task of yielding values to `generatorA` and `generatorB` using the `yield from` keyword. This results in a seamless combination of the outputs of both generators.

By utilizing generator delegation, we can keep our code more modular, readable, and maintainable. It's especially useful when working with nested generators or when you want to combine the outputs of multiple generators in a straightforward manner.

I hope this explanation clarifies the concept of generator delegation for you. If you have any more questions, feel free to ask!

Happy coding!


Hey folks,

I happened to stumble upon this thread and thought I could chip in with my understanding of generator delegation in PHP.

So, generator delegation is a nifty feature in PHP that simplifies working with multiple generators by allowing one generator to yield values from another generator. It's a great way to avoid nesting loops and keep your code cleaner and more manageable.

Here's an example to help illustrate the concept. Let's say we have two generators, `genA` and `genB`, which both yield a sequence of numbers. We want to combine the values from both generators into a single sequence.

function genA() {
yield 1;
yield 2;

function genB() {
yield 3;
yield 4;

function combinedGen() {
yield from genA();
yield from genB();

foreach (combinedGen() as $value) {
echo $value . ' ';

// Output: 1 2 3 4

In the above example, the `combinedGen` function uses `yield from` to delegate the responsibility of generating values to `genA` and `genB`. As a result, when we iterate over `combinedGen()`, it seamlessly yields the combined sequence of values from both generators.

I find generator delegation particularly useful when dealing with complex logic involving multiple generators. It helps keep the code concise, readable, and reduces the need for extra loops or conditional checks.

I hope this explanation offers you some additional insights into generator delegation. Feel free to ask if you have any further questions!

Happy coding!

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