FsmTemplateC

Simple template for C Finite State Machine

About this module

This small Python3 module generates skeleton C code for a finite state machine (FSM). Given a list of states, list of inputs, and a state transition table, the code generated makes it easy to edit and create transition guards and handle inputs. The FSM makes use of look-up tables and does not require searches, exhaustive if-statements, or switch statements.

Prerequisites

Python3 with venv package, setuptools, and Jinja2 are required. A C compiler is required to compile the generated C code (gcc or clang, for example).

Create and/or Activate Virtual Environment

On Linux, run

python3 -m venv .venv
source .venv/bin/activate

On Windows run

python -m venv .venv
.\.venv\Scripts\activate

Install Python Package

python -m pip install -r requirements.txt
python setup.py develop

If you are not developing or debugging, you can also install

python setup.py install

Try it out

First clone the repository

git clone https://github.com/ChisholmKyle/FsmTemplateC && cd FsmTemplateC

To run the example fsm_example.py, on the command line type

cd example
python3 fsm_example.py

and have a look at the output source and header files generated in the newly-created subdirectory fsm_example. Note that the python3 command calls python 3.x and may be different on your machine.

You can also run a basic turnstile state machine. The initial skeleton code is generated from the script turnstile_example.py. The skeleton code was modified to add the appropriate functionality and a complete C code example can be complied from the example/turnstile_complete folder. Assuming make and gcc are installed, compile and run the C code from a terminal as follows:

cd turnstile_complete
make && ./turnstile

The standard terminal output should look like

INPUT   STATE   MESSAGE

-       0
push    0       could not push locked turnstile
-       0
coin    1       unlocked turnstile
-       1
-       1
push    0       locked turnstile
-       0
push    0       could not push locked turnstile
coin    1       unlocked turnstile
coin    1       wasted money on unlocked turnstile
-       1
push    0       locked turnstile

Current Status

This is a minimal and custom implementation which is not intended to replace a more formalized and feature-rich library such as SCM and there's no formal documentation. Only this README, examples, and the generated code have comments that may help you get started. Please feel free to add any features, examples, documentation or fix some bugs!