Concurrency

This section covers FOL’s first shipped V3 concurrency and asynchronous execution subset. Every processor surface is hosted std-only and is implemented with OS threads and Rust standard-library synchronization; FOL does not use a separate async runtime.

Here std-only describes source capability: the artifact uses fol_model = "memo" and the package explicitly declares the bundled internal standard dependency. It does not mean FOL needs std merely to launch a program. Host-compatible core and unhosted memo executables can run too; they simply cannot use processor constructs.

The current chapter split is:

• eventuals
• tasks, channels, select, and mutex parameters

Together they define the language-level model for task execution, coordination, and concurrent ownership boundaries.

The processor pillar is not complete at compiler acceptance. Each row below is also guarded through lowering/runtime behavior, evaluated frontend capability routing, structured diagnostics and explanations, formatter/tool commands, LSP diagnostics/navigation/completion/tokens, Tree-sitter grammar/queries/corpus, tests, docs, and the book. The exact cross-layer mapping lives in Compiler Integration and the repository-level docs/editor-sync.md matrix.

Shipped example inventory

This is the canonical processor example inventory. The milestone chapters and the V3 processor plan link here instead of maintaining smaller lists that can drift. Adding, removing, or renaming a processor example requires updating this published list and the shared machine inventory in test/v3_example_inventory.rs in the same change; compiler integration and editor tests consume that shared machine inventory.

P1: spawn

Positive:

• examples/proc_spawn_m1
• examples/proc_spawn_move_heap_m1
• examples/proc_spawn_canonical_m1
• examples/proc_spawn_detached_m1
• examples/proc_shared_sync_ptr_m1
• examples/proc_spawn_borrow_m1

Negative:

• examples/fail_proc_spawn_detached_borrow_m1
• examples/fail_proc_spawn_fin_m1
• examples/fail_proc_spawn_borrow_mutate_m1
• examples/fail_proc_spawn_weak_m3
• examples/fail_proc_spawn_heap_use_after_move_m1
• examples/fail_proc_spawn_in_core_m1
• examples/fail_proc_spawn_indirect_m1
• examples/fail_proc_spawn_in_memo_m1
• examples/fail_proc_spawn_rc_cross_m1
• examples/fail_proc_spawn_recoverable_m1

P2: channels

Positive:

• examples/proc_channel_capture_m2
• examples/proc_channel_loop_m2
• examples/proc_channel_m2
• examples/proc_channel_pull_m2
• examples/proc_sender_endpoint_m2
• examples/proc_receiver_endpoint_m2

Negative:

• examples/fail_proc_channel_bare_send_m2
• examples/fail_proc_channel_capture_rx_m2
• examples/fail_proc_channel_in_core_m2
• examples/fail_proc_channel_in_memo_m2
• examples/fail_proc_channel_index_m2
• examples/fail_proc_channel_receive_bare_m2
• examples/fail_proc_channel_spawn_consumer_m2
• examples/fail_proc_clone_receiver_m2

P3: select and mutexes

Positive:

• examples/proc_mutex_explicit_unlock_m3
• examples/proc_mutex_local_m3
• examples/proc_mutex_guard_m3
• examples/proc_mutex_guard_end_m3
• examples/proc_mutex_m3
• examples/proc_select_m3

Negative:

• examples/fail_proc_mutex_deferred_m3
• examples/fail_proc_mutex_deferred_forward_m3
• examples/fail_proc_mutex_deferred_lock_m3
• examples/fail_proc_mutex_deferred_unlock_m3
• examples/fail_proc_mutex_double_paren_m3
• examples/fail_proc_mutex_guard_await_m3
• examples/fail_proc_mutex_guard_move_m3
• examples/fail_proc_mutex_in_core_m3
• examples/fail_proc_mutex_in_memo_m3
• examples/fail_proc_select_empty_m3
• examples/fail_proc_select_in_core_m3
• examples/fail_proc_select_in_memo_m3
• examples/fail_proc_select_old_form_m3

P4: eventuals

Positive:

• examples/proc_async_await_m4
• examples/proc_await_error_m4
• examples/proc_evt_named_m4
• examples/proc_evt_lifetime_m4

Negative:

• examples/fail_proc_evt_return_elided_m4
• examples/fail_proc_evt_param_elided_m4
• examples/fail_proc_evt_detached_m4
• examples/fail_proc_evt_embedded_m4
• examples/fail_proc_async_in_core_m4
• examples/fail_proc_async_break_outer_m4
• examples/fail_proc_async_edf_await_m4
• examples/fail_proc_async_indirect_m4
• examples/fail_proc_async_in_memo_m4
• examples/fail_proc_async_nested_capture_m4
• examples/fail_proc_async_recoverable_discard_m4
• examples/fail_proc_async_recoverable_overwrite_m4
• examples/fail_proc_async_recoverable_unawaited_m4
• examples/fail_proc_await_in_core_m4
• examples/fail_proc_await_in_memo_m4
• examples/fail_proc_await_recoverable_discard_m4