sm_retry_logic_1

Demonstrates a state reactor (SrEventCountdown) defined in a superstate. The reactor counts failures across inner state transitions, implementing a 3-attempt retry limit before giving up. This pattern answers the question: can a parent state accumulate event history that persists while its inner states cycle? The answer is yes — and this machine shows how.

What it demonstrates

• SrEventCountdown(3) lives in SsAttemptTask (a superstate), not in any leaf state.
• The reactor counts timer timeouts and explicit ‘f’ keypresses as failures.
• The failure count persists across StIdle ↔ StAttempting inner transitions — it is not reset when the inner states change.
• After 3 total failures (any combination), the superstate transitions to StExhausted.
• Pressing s at any point during an attempt — or while waiting in StIdle — transitions immediately to StSuccess.

State hierarchy

SmRetryLogic1
├── OrTimer    (ClRos2Timer)
└── OrKeyboard (ClKeyboard)

SmRetryLogic1
├── SsAttemptTask  ←  superstate; owns SrEventCountdown(3)
│   │              Reactor input events: EvTimer, EvKeyPressF
│   │              Reactor output event: EvCountdownEnd → StExhausted
│   │              Also reacts: EvKeyPressS → StSuccess
│   │
│   ├── StIdle       (initial)  — waiting for 'n' to start an attempt
│   └── StAttempting            — attempt in progress; 10s timeout
│
├── StSuccess    — reached by pressing 's' at any time
└── StExhausted  — reached after 3 total failures

Build

cd /home/brettpac/workspaces/isaac_ros-dev
colcon build --packages-select sm_retry_logic_1
source install/setup.bash

Launch

ros2 launch sm_retry_logic_1 sm_retry_logic_1.launch.py

This opens two konsole terminals: the state machine node and the keyboard server.

Keyboard controls

Send keystrokes via ROS 2 topic (if not using the konsole keyboard server):

ros2 topic pub /keyboard_unicode std_msgs/msg/UInt16 "data: 110" --once  # n
ros2 topic pub /keyboard_unicode std_msgs/msg/UInt16 "data: 102" --once  # f
ros2 topic pub /keyboard_unicode std_msgs/msg/UInt16 "data: 115" --once  # s

Example walkthroughs

Reach StExhausted via 3 manual failures

Start → StIdle
  → press n → StAttempting
  → press f → StIdle          (failure count: 2 remaining)
  → press n → StAttempting
  → press f → StIdle          (failure count: 1 remaining)
  → press n → StAttempting
  → press f → StExhausted     (failure count: 0, EvCountdownEnd fires)

Reach StExhausted via 3 timer timeouts

Start → StIdle
  → press n → StAttempting → wait 10s → StIdle   (failure count: 2 remaining)
  → press n → StAttempting → wait 10s → StIdle   (failure count: 1 remaining)
  → press n → StAttempting → wait 10s → StExhausted

Reach StSuccess after 2 failures

``` Start → StIdle → press n → StAttempting → press f → StIdle (failure count: 2 remaining) → press n → StAttempting → press f → StIdle (failure count: 1 remaining) → press n → StAttempting

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