> ## Documentation Index
> Fetch the complete documentation index at: https://docs.flumeirc.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Lua Guide

> Writing Flume scripts in Lua

Flume embeds Lua 5.4. Scripts have access to the standard Lua library (string, table, math, os.time/date/clock) with dangerous functions removed for safety.

## Sandbox

The following are **blocked** in Lua scripts:

* `os.execute`, `os.remove`, `os.rename`, `os.getenv`, `os.exit`
* `io.open`, `io.popen`, `io.input`, `io.output`
* `dofile`, `loadfile`
* `debug` library

Use `flume.config.get/set` for persistent storage instead of file I/O.

## Example: Highlight Script

```lua theme={null}
-- highlight.lua
flume.event.on("message", function(e)
    local words = flume.config.get("words") or ""
    for word in words:gmatch("%S+") do
        if e.text:lower():find(word:lower(), 1, true) then
            flume.ui.notify(e.nick .. " mentioned '" .. word .. "'")
        end
    end
end)

flume.command.register("highlight", function(args)
    if args == "" then
        local words = flume.config.get("words") or "(none)"
        flume.buffer.print("", "", "Highlight words: " .. words)
    else
        flume.config.set("words", args)
        flume.buffer.print("", "", "Highlight words set to: " .. args)
    end
end, "View or set highlight words")
```

## Example: Auto-Response

```lua theme={null}
-- autorespond.lua
local responses = {
    ["!help"] = "Try /help for commands",
    ["!source"] = "https://github.com/FlumeIRC/flume",
}

flume.event.on("message", function(e)
    local reply = responses[e.text:lower()]
    if reply then
        flume.channel.say(e.server, e.channel, reply)
    end
end)
```