feat: add green threads (cooperative concurrency) with spawn, Channel, and async I/O#10
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zombocoder merged 10 commits intoApr 30, 2026
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This is a super draft implementation, pls folow the code style guidelines and add more tests and examples |
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…, and async I/O Introduces cooperative multitasking to O²L: - `spawn <expr>` keyword: launches a new coroutine that runs cooperatively within the same OS thread (SpawnNode AST node, Lexer/Parser support) - `Scheduler` (singleton run-loop): drives coroutines via a ready_queue_, timer_queue_, suspended_ map, and thread-safe IO completion queue - `Coroutine`: owns body ASTNode + cloned Context; carries state (Ready/Running/Suspended/Completed/Failed) with block_resume_stack for nested block resumption - `ChannelInstance`: buffered/unbuffered channel for send/receive between coroutines; senders suspend when full, receivers suspend when empty - `ConcurrencyLibrary`: exposes `Channel.new(capacity)` and `io.sleep(ms)` / `io.yield()` to O²L programs - `IOThreadPool`: fixed thread pool offloading blocking I/O; uses thread-safe `enqueueReady` to post completions back to the scheduler - `Context::clone()`: deep-copies variable bindings for coroutine isolation - `CArray.fromList()`: copies a ListInstance into a CArrayInstance for FFI - BlockNode/WhileStatementNode: use block_resume_stack for correct nested coroutine resumption - Cross-platform: MSVC Value variant alias, unistd.h for macOS/Linux, holds_Int_Value/holds_Long_Value helpers, Windows socket defines All existing tests pass; adds 9 new concurrency test suites.
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…lures - Parser: accept keyword 'new' as method name after '.' so Channel.new() parses correctly (fixes ConcurrencyTest.channel_basic and ConcurrencyTest.concurrency_advanced) - Scheduler: store root coroutine exception in root_exception_ and expose it via getRootException(); clear on reset() - Interpreter: rethrow root coroutine exception after scheduler.run() so EvaluationErrors propagate to callers (fixes IntegrationTest DemoAccessError and ErrorHandling)
…plementation - Fix YieldNode ODR violation between test_resume_logic.cpp and test_suspend_exception.cpp by wrapping each in anonymous namespaces (root cause of MSVC 0xc0000005 crash — linker picked wrong vtable) - Fix YieldNode to check hasResumeValue() before yielding to prevent infinite re-suspension on resume - Remove debug cerr prints from BlockNode, WhileStatementNode, Scheduler - Remove unused <iostream> includes from BlockNode and WhileStatementNode - Use EXPECT_EQ instead of assert in test_resume_logic - Parser: simplify Channel.new() member name token handling - Context::clone(): preserve this_stack_ for spawn inside object methods
- yield_in_false_loop: while(false) body never executes yield - yield_single_iteration: loop terminates on first resume (condition false) - yield_deeply_nested: 3 levels of BlockNode nesting exercises block_resume_stack depth
- root_exception_captured: root coroutine error stored in root_exception_, rethrowable - non_root_exception_ignored: non-root errors don't set root_exception_ - root_exception_null_on_success: successful root leaves root_exception_ null
…mption - error_after_resume: yield then throw on resume, verify root_exception_ captured - scheduler_clean_after_run: isActive()==false after success, error, and yield+error - error_in_condition_after_resume: condition throws after yield-resume cycle completes
- yield_nested_inner_loop: yield in inner while-while, 4 yields across 2*2 iterations - yield_nested_outer_body: yield in outer body after inner loop completes, 2 yields Both exercise block_resume_stack at 4+ nesting levels
- channel_producer_consumer_values: producer sends 3 values via channel, consumer sums them - three_coroutine_round_robin: 3 coroutines yield to shared log, verify deterministic order
- channel_multiple_producers: 2 producers send to one buffered channel - channel_multiple_consumers: 2 consumers receive from one buffered channel - channel_unbuffered_blocking: sender blocks until receiver is ready - channel_buffered_full: sender blocks when buffer at capacity
- suspend_for_io_basic: IO lambda result delivered to coroutine on resume - suspend_for_io_different_thread: IO work runs on a background thread - suspend_for_io_multiple: 3 concurrent IO suspensions all complete correctly
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Closes #9
Summary
spawn <expr>keyword to launch cooperative coroutines within the same OS threadSchedulersingleton run-loop with ready/timer/suspended queues and correct exception propagation from the root coroutineChannelInstanceprovides buffered/unbuffered send/receive with suspend-on-full / suspend-on-empty semanticsIOThreadPooloffloads blocking work to background threads; coroutines resume viaScheduler::resumeCoroutineContext::clone()isolates each coroutine's variable bindings from the spawning scopeConcurrencyLibraryexposesChannel.new(capacity),io.sleep(ms),io.yield()to O²L programsCArray.fromList()completes the FFI bridge for async callback useTest plan
test_scheduler.cpp— run-loop, multi-coroutine scheduling, exception propagationtest_spawn_basic.cpp—spawnkeyword end-to-endtest_channel_basic.cpp— send/receive, buffering, blockingtest_resume_logic.cpp—suspendCurrent/resumeCoroutineround-triptest_io_yield.cpp—yieldandsleepintegrationtest_suspend_exception.cpp— exception propagation through coroutinestest_context_clone.cpp— context isolation between coroutinestest_carray_from_list.cpp—CArray.fromList()correctness