10 new tests: state field transitions (ready/suspended/dead), yield from
nested helper function, initial resume arg ignored by ready coroutine,
mutable closure state via dict-set!, complex yield values (list/dict),
round-robin scheduling, factory creates independent coroutines, resuming
non-coroutine raises error.
27/27 pass on both OCaml and JS.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
spec/coroutines.sx: define-library with make-coroutine, coroutine-resume,
coroutine-yield, coroutine?, coroutine-alive?. Built on existing perform/
cek-step-loop/cek-resume suspension machinery.
spec/tests/test-coroutines.sx: 17 tests — multi-yield, final return,
arg passthrough, alive? predicate, nested coroutines, recursive iteration,
independent coroutine interleaving.
Key: coroutine body must use (define loop (fn…)) not named let — named let
transpiles to cek_call→cek_run which rejects IO suspension. All 17/17 pass.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
