LuaBot

A system for running LuaJIT powered FRC and other robots.

Why LuaBot?

Easier than Java/Python. Faster than C++.

LuaBot brings the best of both worlds to FRC robot programming:

Performance

• Faster than C++: Benchmark tests show Lua 1.33x faster than C++ for typical robot code patterns
• LuaJIT magic: JIT compilation to native code with runtime trace optimization
• Zero-copy FFI: Direct C struct access without marshaling overhead
• Optimized hot paths: JIT specializes code paths at runtime better than static compilation

Simplicity

• Less boilersome: No public class, package declarations, or verbose imports
• Cleaner syntax: More concise than Java/C++, more structured than Python
• Dynamic typing: Faster prototyping without type declaration overhead
• Simple class system: local MyClass = class(BaseClass) - that's it
• Direct FFI access: ffi.load() and ffi.cdef() for zero-ceremony C interop

FRC-Optimized

• Command-based framework: Full WPILib command framework with triggers and subsystems
• Hardware abstraction: Complete HAL bindings for all FRC devices
• Simulation support: Full simulator integration with Glass and Driver Station
• No compile times: Edit code and run immediately - perfect for rapid iteration
• Interactive REPL: Debug and test code live while your robot is running

Real Results

-- Benchmark: 2M iterations of robot periodic code
-- Lua:  1.50s
-- C++:  2.00s
-- Result: Lua is 1.33x faster

For FRC teams, this means faster iteration, easier debugging, and better runtime performance - a genuine win across all dimensions.

Building

Dependencies

• CMake - Build system.
• Python - Required for yaml parsing and benchmarking.
• Ninja - Recommended. The build instructions assume you have it.
• Docker - Required to cross-compile LuaJIT for roboRIO
• CCache - Recommended for faster rebuilds.

Get the Code

This projected includes various dependencies as submodules. Make sure to either clone with submodules.

git clone https://github.com/snidercs/luabot --recurse-submodules

Or if you did a normal clone, initialize them

git submodule update --init --recursive

LuaJIT

LuaJIT needs built outside of cmake. We have scripting for that. Linux

sh util/build-luajit-linux.sh

macOS

sh util/build-luajit-macos.sh

Windows TODO: coming soon...

YAML Python

Your system might not have the yaml library for Python.

Build and Run Tests

The steps here are for a Unix based system but should work on any platform with C++.

# Configure the build directory
cmake -Bbuild -GNinja -DCMAKE_BUILD_TYPE=Release

# Compile it
ninja -C build

# Test it
ninja -C build test