wren-lang/wren

---

wren-lang/wren.json

{
  "createdAt": "2013-11-19T00:43:45Z",
  "defaultBranch": "main",
  "description": "The Wren Programming Language. Wren is a small, fast, class-based concurrent scripting language.",
  "fullName": "wren-lang/wren",
  "homepage": "http://wren.io",
  "language": "Wren",
  "name": "wren",
  "pushedAt": "2025-11-19T22:18:55Z",
  "stargazersCount": 7588,
  "topics": [
    "bytecode",
    "c",
    "fibers",
    "interpreter",
    "language",
    "scripting-languages",
    "wren"
  ],
  "updatedAt": "2025-11-25T19:40:42Z",
  "url": "https://github.com/wren-lang/wren"
}

Wren is a small, fast, class-based concurrent scripting language

Think Smalltalk in a Lua-sized package with a dash of Erlang and wrapped up in a familiar, modern [syntax][].

System.print("Hello, world!")

class Wren {
  flyTo(city) {
    System.print("Flying to %(city)")
  }
}

var adjectives = Fiber.new {
  ["small", "clean", "fast"].each {|word| Fiber.yield(word) }
}

while (!adjectives.isDone) System.print(adjectives.call())

• Wren is small. The VM implementation is under [4,000 semicolons][src]. You can skim the whole thing in an afternoon. It’s small, but not dense. It is readable and [lovingly-commented][nan].

• Wren is fast. A fast single-pass compiler to tight bytecode, and a compact object representation help Wren [compete with other dynamic languages][perf].

• Wren is class-based. There are lots of scripting languages out there, but many have unusual or non-existent object models. Wren places [classes][] front and center.

• Wren is concurrent. Lightweight [fibers][] are core to the execution model and let you organize your program into an army of communicating coroutines.

• Wren is a scripting language. Wren is intended for embedding in applications. It has no dependencies, a small standard library, and [an easy-to-use C API][embedding]. It compiles cleanly as C99, C++98 or anything later.

If you like the sound of this, [let’s get started][started]. You can even try it [in your browser][browser]! Excited? Well, come on and [get involved][contribute]!

[syntax] !: http://wren.io/syntax.html [src] !: https://github.com/wren-lang/wren/tree/main/src [nan] !: https://github.com/wren-lang/wren/blob/93dac9132773c5bc0bbe92df5ccbff14da9d25a6/src/vm/wren_value.h#L486-L541 [perf] !: http://wren.io/performance.html [classes] !: http://wren.io/classes.html [fibers] !: http://wren.io/concurrency.html [embedding] !: http://wren.io/embedding/ [started] !: http://wren.io/getting-started.html [browser] !: http://ppvk.github.io/wren-nest/ [contribute] !: http://wren.io/contributing.html