Generate consistent, idiomatic communication protocol code from a JSON specification.
Supports communication between embedded systems and host machines (e.g. ESP ↔ PC), with code generation for multiple languages like C and Go.

Overview

Define your messages once in a simple JSON format, and generate code to handle:

Typed payload structs
Message ID enums
Dispatcher logic
Send & receive helpers

Message Package Format

Currently, the protocol structure is statically defined as:

start_byte
message_length
payload
checksum

Message Definition Format (JSON)

Each message is described as:

{
  "name": "Status",
  "id": "0xE2",
  "payload": [
    { "name": "clientid", "type": "uint8_t" },
    { "name": "mac", "type": "uint8_t[6]" }
  ]
}

Code Generation

Current: C (ESP → PC)

Header file with MessageID enums (ESP_TO_PC, PC_TO_ESP)
Typed payload structs
Union of all payloads
Hook declarations for incoming messages
Message dispatcher (switch on MessageID)
Send functions per message

Uses casting for payloads — fast but not fault-tolerant.

Planned: Go (PC → ESP)

Generate constants for MessageID
Define structs for payloads (consider endianess!)
Dispatcher switch logic
Hook functions
Send functions
Explore alternatives to unions (e.g., interfaces)

Go is less constrained, so performance isn't the top priority.

Planned: ESP ↔ ESP (C, ESP-NOW)

Separate enums for MasterToSlave, SlaveToMaster
Shared payload format
Union for all message types
Dispatcher on MessageID
Role-specific send functions

Implemented

Code-Generierung für C (ESP → PC)
- Header-Dateien mit Enums
- Payload-Structs
- Union-Typen
- Hook-Funktionen
- Message-Dispatcher (Switch-Case)
- Send-Funktionen
- Generate Header and Source File

To-Do

Language Support: Go

MessageID generation (iota)
Payload structs
Endianess handling
Dispatcher
Hooks & senders
Union alternative

ESP-to-ESP

Master/Slave Message IDs
Shared payload definitions
Dispatcher & send logic

Generator Features

Direction config (esp→pc, etc.)
Configurable package structure (e.g. start_byte, checksum)
Field type aliases (u8, uint8_t, etc.)
Support for optional fields / versioning

JSON Format

JSON schema for validation
Field descriptions
Global protocol settings (endianness, direction)
Multi-message support

Tooling

CLI interface (--input, --output, --language, ...)
Logging / verbose mode
Build script / Makefile

Testing

Unit tests for generator
JSON test inputs (esp→pc, pc→esp, etc.)
Golden files for regression testing
Use Generated Code in actual Project

Roadmap Ideas

Add checksum algorithm config
Integration with code linters or CI