statechart's Introduction

C++ StateChart Library

StateCharts (Harel, 1987) is a visual formalism for declarative description of complex interactive systems. It extends the conventional state machine formalism with Hierarchy, Concurrency and Communication.

SCXML is a W3C standard based on StateCharts. This is a C++ library that implements the SCXML specification. Instead of XML, a StateChart is represented as a StateChart protobuf.

Features

Many features from the SCXML standard have been implemented.

Composite State
Parallel State
Datamodel
Transitions (Conditional, Eventless)
Executable Statements (Raise, Log, Assign, If, ForEach, Send)
Serialize/Deserialize the state machine

TODO

History

Example

Here's an example of a StateChart that describes a Microwave.

You can see //statechart/example/microwave_example_main.cc for details on how to specify such a StateChart as a StateChart proto and how to use it in code.

Usage

To build the library you'll need bazel. You can download and install it from here.

# Download/Clone the repo.
git clone https://github.com/google/statechart.git
cd statechart

# Build the library
bazel build //statechart/...

# Run unit tests
bazel test //statechart/...

# Run the Microwave example
bazel run //statechart/example:microwave_example_main -- --alsologtostderr

Disclaimer

This is not an officially supported Google product.

References

David Harel, 1987, Statecharts: a visual formalism for complex systems, Science of Computer Programming. Link
State Chart XML (SCXML): State Machine Notation for Control Abstraction. Link

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