actor-zeta

C++20 actor model with coroutines, PMR allocators, and no RTTI/exceptions.

Features

• Coroutines: co_await, co_return, co_yield
• unique_future: Async request-response
• generator: Streaming data between actors
• std::pmr: Memory resource allocation
• No RTTI/exceptions: -fno-rtti -fno-exceptions

Requirements

• C++20 (GCC 11+, Clang 12+)
• CMake >= 3.15
• Conan 2.x

Quick Start

Request-Response

class Worker : public actor_zeta::basic_actor<Worker> {
public:
    actor_zeta::unique_future<int> compute(int x) {
        co_return x * 2;
    }

    using dispatch_traits = actor_zeta::dispatch_traits<&Worker::compute>;

    explicit Worker(std::pmr::memory_resource* res)
        : actor_zeta::basic_actor<Worker>(res) {}

    actor_zeta::behavior_t behavior(actor_zeta::mailbox::message* msg) {
        if (msg->command() == actor_zeta::msg_id<Worker, &Worker::compute>) {
            co_await actor_zeta::dispatch(this, &Worker::compute, msg);
        }
    }
};

// Usage - send() returns pair<bool, future>
auto [needs_sched, future] = actor_zeta::send(worker.get(), &Worker::compute, 42);
if (needs_sched) scheduler->enqueue(worker.get());
int result = co_await std::move(future);

Streaming

class Producer : public actor_zeta::basic_actor<Producer> {
public:
    actor_zeta::generator<int> stream(int count) {
        for (int i = 0; i < count; ++i) {
            co_yield i;
        }
    }

    using dispatch_traits = actor_zeta::dispatch_traits<&Producer::stream>;

    explicit Producer(std::pmr::memory_resource* res)
        : actor_zeta::basic_actor<Producer>(res) {}

    actor_zeta::behavior_t behavior(actor_zeta::mailbox::message* msg) {
        if (msg->command() == actor_zeta::msg_id<Producer, &Producer::stream>) {
            co_await actor_zeta::dispatch(this, &Producer::stream, msg);
        }
    }
};

// Usage - send() returns pair<bool, generator>
auto [needs_sched, gen] = actor_zeta::send(producer.get(), &Producer::stream, 10);
if (needs_sched) scheduler->enqueue(producer.get());
while (co_await gen) {
    process(gen.current());
}

Build

conan profile detect --force
conan install . -of build -s build_type=Debug --build=missing

cmake -B build -GNinja \
  -DCMAKE_BUILD_TYPE=Debug \
  -DALLOW_TESTS=ON \
  -DCMAKE_TOOLCHAIN_FILE=./build/Debug/generators/conan_toolchain.cmake

cmake --build build
ctest --test-dir build --output-on-failure

CMake Options

Option	Default	Description
ALLOW_EXAMPLES	OFF	Build examples
ALLOW_TESTS	OFF	Build tests
RTTI_DISABLE	ON	-fno-rtti
EXCEPTIONS_DISABLE	ON	-fno-exceptions

Documentation

• CLAUDE.md - Development guide
• PROMISE_FUTURE_GUIDE.md - Request-response patterns
• GENERATOR_GUIDE.md - Streaming patterns
• CHANGELOG.md - Change history

License

BSD-3-Clause license