v0.2.0

Added

• Program type — a builder-style API for assembling and running effect-handled computations. This is now the recommended way to use the library for most users.

  The key feature is incremental handler attachment: handlers are added one at a time via .handle(), which means a partially-handled program is a first-class value you can pass around, store, or extend later. The compiler tracks which effects are still unhandled and only permits running the computation once all effects have a handler.

  // Define a computation once...
  let program = Program::new(|yielder: Yielder<'_, Effs>| async move {
      let n = yielder.yield_(Counter).await;
      let answer = yielder.yield_(Ask("question")).await;
      (answer, n)
  });
  
  // ...attach handlers incrementally, e.g. in different modules or call sites...
  let program = program.handle(|_: Counter| CoControl::resume(42u64));
  let program = program.handle(|_: Ask| CoControl::resume("yes"));
  
  // ...and run only when all effects are handled.
  let result = program.run_sync();

  Available constructors and methods:

  • Program::new(f) — creates a program from an async closure
  • Program::new_send(f) — creates a Send-able program (for use with tokio::spawn)
  • Program::from_co(co) — wraps an existing Co/CoSend coroutine
  • .handle(handler) — attaches the next handler (in effect declaration order); type-checked at compile time
  • .run_sync() — executes synchronously, returns Result<R, Cancelled>
  • .run_sync_stateful(&mut state) — executes synchronously with shared mutable state
  • .run() — executes asynchronously, returns Result<R, Cancelled>
  • .run_stateful(&mut state) — executes asynchronously with shared mutable state

• handle free function — functional alternative to .handle(), useful when incrementally building up a program across call sites without method chaining:

  let p = handle(p, |_: Counter| CoControl::resume(42u64));
  let p = handle(p, |_: Ask| CoControl::resume("yes"));
  p.run_sync()

• All public items are now documented.

Full Changelog: v0.1.0...v0.2.0