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	67ms	4ms	Go (native)
Tengo	3,104ms	5ms	VM on Go
Lua	1,754ms	3ms	Lua (native)
go-lua	5,121ms	5ms	Lua VM on Go
GopherLua	5,499ms	5ms	Lua VM on Go
Python	2,859ms	26ms	Python (native)
starlark-go	16,846ms	5ms	Python-like Interpreter on Go
gpython	18,638ms	6ms	Python Interpreter on Go
goja	6,626ms	5ms	JS VM on Go
otto	88,489ms	13ms	JS Interpreter on Go
Anko	108,415ms	15ms	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