Amp is a non-blocking concurrency framework for PHP. It provides an event loop, promises and streams as a base for asynchronous programming.
Promises in combination with generators are used to build coroutines, which allow writing asynchronous code just like synchronous code, without any callbacks.
The weak link when managing concurrency is humans; we simply don't think asynchronously or in parallel. Instead, we're really good at doing one thing at a time and the world around us generally fits this model. So to effectively design for concurrent processing in our code we have a couple of options:
1. Get smarter (not feasible);
2. Abstract concurrent task execution to make it feel synchronous.
Amp provides an [event loop](./event-loop/README.md), [promises](./promises/README.md) and [asynchronous iterators](./iterators/README.md) as building blocks for (fully) asynchronous libraries and applications. [Coroutines](./coroutines/README.md) make asynchronous code feel as synchronous code.