CXXStateTree

Modern Hierarchical State Machine for C++20

🚀 Features

• 🔧 Fluent builder API with lambda-based DSL
• ⚡ Fast runtime performance with zero heap allocation
• 🛡️ Optional guards and actions for transitions
• 🔄 Event-based state transitions
• 🧪 Google Test integration
• 📈 Code coverage with Codecov
• 🌳 Designed for extensibility: nested states, DOT export coming soon
• 🔧 Deployed as Shared Library and as Single Header-Only library

🛠️ Quick Example

#include <iostream>
#include "CXXStateTree/StateTree.hpp"

using namespace CXXStateTree;

int main() {
    auto machine = StateTree::Builder()
        .initial("Idle")
        .state("Idle", [](State& s) {
            s.on("Start", "Running", nullptr, []() {
                std::cout << "Idle -> Running" << std::endl;
            });
        })
        .state("Running", [](State& s) {
            s.on("Stop", "Idle", nullptr, []() {
                std::cout << "Running -> Idle" << std::endl;
            });
        })
        .build();

    machine.send("Start");
    machine.send("Stop");
}

🛠️ Building Shared Library

cmake -S . -B build 
cmake --build build

After these command the Shared Library can be found in build directory

Please Note: in future release cmake will have the ability to install the library automatically, for now it is necessary to do it manually

🛠️ Building Single Header-Only Library

cmake -S . -B build -DENABLE_SINGLE_HEADER=ON
cmake --build build

After these command the Single Header-Only Library can be found in single_include directory with the name CXXStateTree.hpp

Please Note: in future release cmake will have the ability to install the library automatically, for now it is necessary to do it manually

🧪 Running Tests

cmake -S . -B build -DENABLE_TEST=ON -DENABLE_COVERAGE=ON
cmake --build build
cd build && ctest

📦 Dependencies

• C++20 compiler (GCC >= 10, Clang >= 11, MSVC >= 2019)
• GoogleTest (auto-downloaded via CMake)

📈 Code Coverage

📂 Directory Structure

CXXStateTree/
├── include/CXXStateTree/     # Public header-only API
├── examples/                 # Usage examples
├── tests/                    # Google Test suite
├── CMakeLists.txt            # Project build
└── .github/workflows/ci.yml  # GitHub Actions CI

📋 License

MPL2.0 License — see LICENSE for details.

🌟 Coming Soon

• Nested (hierarchical) state support
• DOT/Graphviz state diagram export
• Transitions with context/parameters

👋 Contributions Welcome

Issues, feature suggestions, and PRs are welcome!