state machines on arduino: finite state machines, hierarchical state machines, event driven programming, ...

[milahu]

state machines generators

the state machine is generated on compiletime

• SCXML format ("statechart XML format") (wikipedia) (w3c) - hierarchical state machines, parallel state machines, ... should be feature-complete for most use cases. the state machines are declared in XML, which can be compiled to efficient C or C++ code
  • https://github.com/shuvalov-mdb/xstate-cpp-generator - generate C++ code from scxml spec, implemented in javascript (hackable!)
  • https://doc.qt.io/qt-5/qscxmlc.html - Qt SCXML Compiler - generate C++ code from scxml spec
  • https://github.com/jp-embedded/scxmlcc - generate C++ code from scxml spec
    • more-or-less abandoned (or stable) since year 2019
  • https://github.com/tklab-tud/uscxml#for-transformations - generate C++ code from scxml spec
    • last push in year 2019 = abandoned project with serious bugs, for example Huge memory leak with 'Xerces::getTextContent' tklab-tud/uscxml#179 (fixed in alexzhornyak's fork)
    • http://tklab-tud.github.io/uscxml/embedded.html SCXML on an ATMega328
• statechart format. based on protobuf (the "protocol buffers" binary protocol), not XML. ancestor of scxml
  • https://github.com/google/statechart in c++
  • https://github.com/AlexandreDecan/sismic - Statechart Model Interpreter and Checker
  • https://github.com/cmars/statechart - statecharts in rust
• https://github.com/jonasblixt/ufsm - generate C code from xml spec (custom format, not scxml)

state machine interpreters

the state machine is generated on runtime

• https://doc.qt.io/qt-5/qtscxml-index.html - both interpreter and compiler
• https://github.com/zen747/scm - scxml in C++. only runtime interpreter, no code generator
• https://github.com/BehaviorTree/BehaviorTree.CPP - custom XML format

state machine theory

• https://stackoverflow.com/questions/133214/is-there-a-typical-state-machine-implementation-pattern

event driven programming

aka: reactive programming, non-blocking code, parallel computing, async code, embedded operating systems, parallel state machines

• https://github.com/igormiktor/arduino-EventManager [already listed in Awesome-arduino] EventManager is a single C++ class that provides an event handling system for Arduino. With EventManager you can register functions that "listen" for particular events and when things happen you can "post" events to EventManager. You then use the loop() function to regularly tell EventManager to process events and the appropriate listeners will be called.
• https://github.com/mikaelpatel/Cosa - Cosa is an object-oriented platform for Arduino. It replaces the Arduino and Wiring library with a large set of integrated classes that support the full range of AVR/ATmega/ATtiny internal hardware modules ... Cosa supports several programming paradigms including Multi-Tasking, Event Driven Programming and UML Capsules/Actors.
• https://github.com/tinkerspy/Automaton/wiki - Reactive State Machine Framework for Arduino. The Automaton framework allows you to create Arduino applications that consist entirely of concurrently running components (finite state machines) interacting with one another. Changes are automatically propagated through the application like changes in a spreadsheet. Encourages modular design and separation of concerns
• https://github.com/johnnyb/Eventually - make a more event-oriented environment for Arduino programming. To make it actually easy to use to build worthwhile projects.
• https://github.com/kmilo17pet/QuarkTS - operating system that provides a modern environment to build stable and predictable event-driven multitasking embedded software. Due to its size and features, is intended to play in the space between RTOSes and bare-metal. QuarkTS was written for embedded developers who want more functionality than what existing task schedulers offer, but want to avoid the space and complexity of a full RTOS, keeping the taste of a robust and safe one.
• https://github.com/QuantumLeaps/qpc - "quantum leap" real-time embedded framework/RTOS for embedded systems based on active objects (actors) and hierarchical state machines
  • https://github.com/QuantumLeaps/qpcpp
  • Event-Driven Arduino Programming with QP™-nano and QM™ - "Luckily, generations of programmers before you have discovered an effective way of solving the “spaghetti” code problem. The solution is based on the concept of a state machine, or actually a set of collaborating state machines that preserve the context from one event to the next using the concept of state. This QP™-nano framework described in the next section allows you to combine the event-driven programming paradigm with modern state machines."
  • event-driven arduino programming
• https://en.wikipedia.org/wiki/Event-driven_finite-state_machine
• https://arduino.stackexchange.com/questions/18072/event-driven-programming
  • http://blog.ardublock.com/2013/10/29/evaluating-of-event-driven-libraries-on-arduino/

visual simulators

edit the state machine as text file, and get a graphical simulation

• SCXML format
  • https://github.com/statelyai/xstate-viz (live demo) - state machine visualizer / simulator, runs in the browser
  • https://github.com/statelyai/xstate#hierarchical-nested-state-machines in javascript
    • useful to implement graphical state machine editors (visual programming)
    • can be used to implement C++ code generators
      • https://github.com/shuvalov-mdb/xstate-cpp-generator
    • https://github.com/darrylhebbes/awesome_xstate

visual editors

• https://github.com/fmorbini/scxmlgui
• visual editor in Qt Creator
• QM™ Graphical Modeling Tool - QM™ (Quantum Modeler) is a free, cross-platform, graphical modeling tool for designing and implementing real-time embedded applications based on the QP™ state machine frameworks. ... QM™ eliminates coding errors by automatic generation of compact C or C++ code that is 100% traceable from your design.

specify state machines in c++

these solutions are rather verbose = more work

• https://github.com/tinkerspy/Automaton - focus on arduino [already listed in Awesome-arduino]
• https://github.com/kiprasmel/xstate-cpp - "scxml" in C++. new project. not-yet import from scxml
• https://github.com/boost-ext/sml
• https://github.com/digint/tinyfsm
• https://github.com/andrew-gresyk/HFSM2 High-Performance Hierarchical Finite State Machine
• https://github.com/kiishor/UML-State-Machine-in-C
• https://github.com/tinverse/tsm

related

• https://stackoverflow.com/questions/1793511/is-there-a-programming-language-with-built-in-state-machine-construct
• https://github.com/topics/hierarchical-state-machine