Style Guide

This page is a code style guide for the HybridController Firmware.

Entrypoints and Seperations

• src/hybrid-controller.cpp is the main entry point for regular usage.
• All (unit/integration/etc) tests below test/ are also entry points on its own.
• Code is highly capsulated in different "modules" within the lib/ directory.

Formatting

• The code generally uses 2 whitespaces as intend. However, clang-format shall be used.
• Use C++ features wisely. Don't end up in template hell.

Communication Concepts

• JSON lines as universal protocol for communicating with the microcontroller (basically for anything: Logging, Remote Procedure Calls, etc.). We therefore also stick to ASCII whenever possible.
• The USB serial console is always treated as an administrative interface. Reason: Whoever has access to the serial console also has physical access to the microcontroller.

Strings

• Prefer STL to Arduino libraries wherever possible, for instance prefer std::string over Arduinos String.
• Prefer Arduinos Printable interface over memory-intensive string serialization.
• Prefer to use JSON Custom Converters in favour of some toJSON methods.

The Heap in general

This code does not save on new and malloc calls. There is lot to improve here. Could employ more ETL instead of STL.

Strings/Buffer vs. Streams

TODO, write about

• Buffers such as ArduinoJSON with their document concept
• Streaming data which avoids in-memory preparation