go_channels library

Go-style concurrency for Dart: typed Channels, a faithful select, and structured task scopes with cancellation.

Classes

CancelToken: A cooperative cancellation signal.
Channel<T>: A CSP-style channel that carries values of type T between asynchronous tasks, modelled on Go's channels.
SelectCases<R>: Collects the branches of a select. Register a receive with onReceive, a send with onSend, a non-blocking fallback with onDefault, and a deadline with onTimeout.
TaskScope: A structured-concurrency scope: a group of tasks that all finish before the scope returns, and where one failure cancels the rest (fail-fast).

select<R>(void build(SelectCases<R> cases)) → Future<R>: Waits on several channel operations at once and runs exactly one, modelled on Go's select. Register branches with the SelectCases builder:
waitAll<T>(Iterable<FutureOr<T> Function(CancelToken token)> tasks, {CancelToken? parent}) → Future<List<T>>: Runs tasks concurrently under one scope and returns their results in order. Fails fast: the first error cancels the rest and is rethrown.
withTaskScope<R>(FutureOr<R> body(TaskScope scope), {CancelToken? parent}) → Future<R>: Runs body in a fresh TaskScope and returns its result once every task spawned inside has finished.
withTimeout<T>(Duration duration, FutureOr<T> task(CancelToken token), {CancelToken? parent}) → Future<T>: Runs task with a token that is cancelled after duration.

CancelledException: Thrown by CancelToken.throwIfCancelled when a token has been cancelled.
ChannelClosedError: Thrown by Channel.receive when the channel is closed and no values are left to drain. Use Channel.receiveOr or Channel.stream if you would rather observe closure without an exception.