A fast script language for Go
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The Tengo Language

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Tengo is a small, dynamic, fast, secure script language for Go.

Tengo is fast and secure because it's compiled/executed as bytecode on stack-based VM that's written in native Go.

/* The Tengo Language */

each := func(seq, fn) {
    for x in seq { fn(x) }

sum := func(init, seq) {
    each(seq, func(x) { init += x })
    return init

n := sum(0, [1, 2, 3])   // == 6
s := sum("", [1, 2, 3])  // == "123"

Run this code in the Playground


  • Simple and highly readable Syntax
    • Dynamic typing with type coercion
    • Higher-order functions and closures
    • Immutable values
    • Garbage collection
  • Securely Embeddable and Extensible
  • Compiler/runtime written in native Go (no external deps or cgo)
  • Executable as a standalone language / REPL


fib(35) fibt(35) Type
Go 58ms 4ms Go (native)
Tengo 4,180ms 5ms VM on Go
Lua 1,695ms 3ms Lua (native)
go-lua 5,163ms 5ms Lua VM on Go
GopherLua 5,525ms 5ms Lua VM on Go
Python 3,097ms 27ms Python (native)
starlark-go 15,307ms 5ms Python-like Interpreter on Go
gpython 17,656ms 5ms Python Interpreter on Go
goja 6,876ms 5ms JS VM on Go
otto 81,886ms 12ms JS Interpreter on Go
Anko 97,517ms 14ms Interpreter on Go

* fib(35): Fibonacci(35)
* fibt(35): tail-call version of Fibonacci(35)
* Go does not read the source code from file, while all other cases do
* See here for commands/codes used