Lua for LiaScript: Execute Lua Scripts Interactively in the Browser

Lua is lightweight, fast, embeddable, and widely used — in game development (Roblox, World of Warcraft, Löve2D), embedded systems, configuration scripting, and teaching. Its simple syntax and minimal runtime make it an excellent first language.

The Lua template brings a complete Lua virtual machine to LiaScript, based on an Emscripten port of the reference Lua interpreter. Code runs entirely in the browser, no server needed.

Quick Start

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One macro: @Lua.eval.

@Lua.eval — Execute Lua Code

Attach @Lua.eval to any Lua code block. The block becomes editable and executable; output from print() appears in the console.

```lua
print("Hello from Lua!")

for i = 1, 5 do
  print(i .. "^2 = " .. i*i)
end
```
@Lua.eval

JavaScript Interoperability

The Lua VM runs inside the browser JavaScript environment, which means Lua code has direct access to browser globals via the js library. This is a unique feature that enables cross-language experiments.

```lua
-- Access the browser window object
local window = js.global

-- Alert dialog
window:alert("Hello from Lua!")

-- Screen information
local screen = js.global.screen
print("Screen: " .. screen.width .. "x" .. screen.height)

-- Current time
print("Time: " .. js.global.Date.now())

-- Run JavaScript from Lua
local result = js.global:eval("[1,2,3,4,5][2]")
print("JS array index 2: " .. tostring(result))
```
@Lua.eval

This is especially useful in courses that compare languages: students can see how the same operation works in both Lua and JavaScript.

Full Template Demo

Use Cases

Introductory scripting — Lua’s syntax is minimal and readable. Variables, functions, loops, and tables are enough to teach core programming concepts without syntactic overhead.

Game development courses — Lua is the scripting language for Roblox and many game engines. Introduce game logic concepts — state machines, event handlers, entity systems — with real Lua syntax.

Embedded systems and scripting — Lua is widely used as an embedded scripting engine (OpenWrt, Redis scripting, Nginx/OpenResty). Teach configuration scripting in a relevant language.

Cross-language comparison — The JavaScript interop (js.global) makes it practical to show the same operation in both Lua and JavaScript side by side in a LiaScript course.

Technical Facts

Try It

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