Concurrency

Kairo's concurrency system provides async/await, coroutines, and thread-level primitives. The following features are planned and referenced across the existing documentation:

Async/Await

The async modifier on functions and the await keyword for waiting on asynchronous results. See Functions for the async modifier.

Coroutines (yield)

Functions with a yield T return type are generators: they produce values cooperatively. The yield keyword suspends the function and produces a value to the caller. See Generators for the rules.

spawn

Launching concurrent work. Syntax and runtime model (green threads, OS threads, or event loop) are being finalized.

Atomic Types (atomic T)

Thread-safe wrapper type for lock-free operations. Referenced in Functions.

Thread-Local Variables

See Thread-Local Variables.

Synchronization Primitives

Mutexes, channels, and other coordination mechanisms will be documented here once the standard library concurrency API is finalized.

Custom Awaitables

Classes can define fn <T> op await(self, obj: std::forward<T>) -> T to customize the behavior of await when called on an instance. See Operators for the op await overload.

await async_fn()       // syntax sugar for a state machine
spawn some_async_fn()  // syntax sugar for detaching a thread
yield some_value       // syntax sugar for a coroutine, function must have yield on return type

fn get_tokens() -> yield string {
    yield "token1"
    yield "token2"
}

op await is overloadable: fn op await (self) -> T for custom async types.

• await async_fn() syntax sugar for state machine
• spawn some_async_fn() syntax sugar for detaching a thread
• yield some_value coroutine syntax, function must have -> yield T return type
• fn op await (self) -> T overloadable for custom async types
• atomic T thread-safe wrapper type

See also

• Threading
• Generators
• Function Declarations
• Operator Overloading
• Closures
• Ownership
• Panic