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 */

fmt := import("fmt")

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

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

fmt.println(sum(0, [1, 2, 3]))   // "6"
fmt.println(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
• Use cases: rules engine, state machine, gaming, data pipeline, transpiler

Benchmark

	fib(35)	fibt(35)	Type
Go	65ms	4ms	Go (native)
Tengo	2,786ms	5ms	VM on Go
Lua	1,775ms	3ms	Lua (native)
go-lua	5,173ms	5ms	Lua VM on Go
GopherLua	5,392ms	5ms	Lua VM on Go
Python	2,865ms	26ms	Python (native)
starlark-go	16,716ms	11ms	Python-like Interpreter on Go
gpython	18,709ms	6ms	Python Interpreter on Go
goja	6,773ms	13ms	JS VM on Go
otto	87,592ms	13ms	JS Interpreter on Go
Anko	107,647ms	22ms	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
• Object Types
• Runtime Types and Operators
• Builtin Functions
• Interoperability
• Tengo CLI
• Standard Library