The Tengo Language

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

Features

• 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

Benchmark

	fib(35)	fibt(35)	Type
Go	58ms	4ms	Go (native)
Tengo	4,334ms	5ms	VM on Go
Lua	1,740ms	3ms	Lua (native)
go-lua	5,229ms	5ms	Lua VM on Go
GopherLua	5,486ms	5ms	Lua VM on Go
Python	3,116ms	27ms	Python (native)
starlark-go	15,414ms	5ms	Python-like Interpreter on Go
gpython	17,754ms	6ms	Python Interpreter on Go
goja	6,843ms	6ms	JS VM on Go
otto	86,542ms	13ms	JS Interpreter on Go
Anko	98,962ms	26ms	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

References

• Language Syntax
• Tengo Objects
• Runtime Types
• Builtin Functions
• Interoperability
• Tengo CLI
• Standard Library

Roadmap

v0. (Current)

Things are experimental, and, the focus is on the core language features, stability, basic interoperability, and the performance optimization.

v1. Tengo as a Script Language

This will be the first versioned release, and, the main goal for v1 is to make Tengo as a fast embeddable script language for Go, which means Tengo will be comparable to other Go-based script languages such as Starlark, Lua VMs, and other interpreters.

• Interoperability with Go code
• Sandbox environment
• More language features

v2. Tengo as a Standalone Language

• Language-level concurrency support
• Tengo Standard Libraries
• Native executables compilation
• More language features