Execution Requirements: Motion and Timing

4. Motion Execution Requirements

Status: Reviewed (2026-03-11 review pass)

Per-command review:

• how G0/G1/G2/G3 become normalized execution commands
• what source information must be carried
• what effective modal state must be attached
• when motion submission blocks
• what completion/cancel behavior is required

Reviewed decisions:

• G0 and G1 should normalize into explicit linear-move command structures
• G2 and G3 should normalize into explicit arc-move command structures
• normalized motion commands should be sent through the runtime interface boundary rather than exposing raw parser words downstream
• motion commands must carry source information including:
  • source file/path if known
  • physical input line number
  • block number N... if present
• motion commands must carry all effective supported modal-group values
• motion submission follows the general async action-command pattern:
  • Ready: accepted and execution can continue
  • Pending: accepted and engine enters Blocked
  • Error: execution faults
• in the async model, Pending means the motion command was accepted by the runtime boundary, not necessarily physically completed
• Pending does not mean “retry the same motion submission later from the engine/session side”
• once runtime/external logic resolves the pending motion, resume(...) continues execution
• readiness for a pending motion token is determined by the embedding runtime or run manager, not by the library
• resume(...) must continue from the existing blocked execution state; it must not resubmit the original motion command
• resume(...) should be invoked by the thread that owns the execution session/engine
• for queue-backed runtimes, a valid readiness condition is that the held move was successfully pushed into the downstream queue
• the runtime boundary is a poor fit for long blocking inside motion-submission calls; the preferred design is to return Pending quickly and manage the wait asynchronously on the runtime side
• cancel() should attempt runtime cancellation of in-flight motion/wait and then move the engine to Cancelled

Review note:

• the remaining follow-up is mainly command-field layout design, since the behavioral contract is now reviewed

5. Dwell / Timing Execution Requirements

Status: Reviewed (2026-03-11 review pass)

Requirements to review:

• how G4 becomes a normalized dwell/timing command
• what source information must be carried
• what effective modal/timing state must be attached, if any
• when dwell submission blocks
• what completion/cancel behavior is required

Reviewed decisions:

• G4 should normalize into an explicit dwell/timing command structure
• normalized dwell/timing commands should be sent through the runtime interface boundary rather than exposing raw parser words downstream
• dwell/timing commands must carry source information including:
  • source file/path if known
  • physical input line number
  • block number N... if present
• dwell/timing commands must carry all effective supported modal-group values under the general execution-state rule
• dwell/timing submission follows the general async action-command pattern:
  • Ready: accepted and execution can continue
  • Pending: accepted and engine enters Blocked
  • Error: execution faults
• in the async model, Pending means the dwell/timing command was accepted by the runtime boundary, not necessarily fully completed
• Pending does not mean “retry the same dwell/timing submission later from the engine/session side”
• once runtime/external logic resolves the pending dwell/timing action, resume(...) continues execution
• readiness for a pending dwell/timing token is determined by the embedding runtime or run manager, not by the library
• resume(...) must continue from the existing blocked execution state; it must not resubmit the original dwell/timing command
• cancel() should attempt runtime cancellation of in-flight dwell/timing wait and then move the engine to Cancelled

Review note:

• the remaining follow-up is mainly dwell-command field layout design, since the behavioral contract is now reviewed