How Lua Chips Work

Lifecycle

When you save Lua code to a chip, it goes through a well-defined lifecycle:

1. Compile & Initialize

When code is saved (or the housing powers on), StationeersLua:

1. Creates a fresh Lua 5.2 VM for the chip
2. Opens sandboxed standard libraries (math, string, table, etc.)
3. Injects the ic API table with all device functions, enums, and networking
4. Runs your module-level code (everything outside tick()) with a budget of 500,000 instructions

-- This code runs ONCE during initialization
local LT = ic.enums.LogicType
local threshold = 25.0
print("Script initialized!")  -- Printed once

-- tick() is called every game tick after init
function tick(dt)
    -- ...
end

2. Tick Loop

Every game tick (~0.5 seconds), the runtime performs these steps in order:

1. Network messages — Incoming messages from other Lua chips are delivered to handlers
2. Events — Registered event handlers are dispatched
3. Main coroutine — If the script used sleep() or yield(), the coroutine is resumed
4. tick(dt) — If a global tick function is defined, it's called with the delta time

Each tick has a budget of 50,000 instructions.

3. Shutdown

The Lua VM is destroyed when:

• The IC Housing is powered off or loses power
• The chip is removed from the housing
• The game exits

Key Rules

Server-Authoritative

All Lua execution happens on the server/host. In multiplayer, clients never run Lua code — they see the results via normal game state synchronization (device values, display names, etc.).

Power-Gated

If the IC Housing is off or unpowered, the script will not:

• Compile or initialize
• Tick or process events
• Respond to network messages

The chip effectively doesn't exist until the housing has power and is switched on.

Deterministic Sandbox

Lua chips run in a restricted environment:

• No filesystem I/O — io, dofile, loadfile are blocked
• No process control — os.execute, os.exit are blocked
• No threads — Only sleep/yield for pausing (coroutine-based)
• No require from files — require() loads from library chips on the data network, not from disk

Advanced Computing Compatibility

If the Advanced Computing mod is installed, chip stacks support extended device pins d0–d11 and rack self-addressing at d100+. StationeersLua fully supports these extended indices.