tengo

README

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	48ms	3ms	Go (native)
Tengo	2,349ms	5ms	VM on Go
Lua	1,416ms	3ms	Lua (native)
go-lua	4,402ms	5ms	Lua VM on Go
GopherLua	4,023ms	5ms	Lua VM on Go
Python	2,588ms	26ms	Python (native)
starlark-go	11,126ms	6ms	Python-like Interpreter on Go
gpython	15,035ms	4ms	Python Interpreter on Go
goja	5,089ms	5ms	JS VM on Go
otto	68,377ms	11ms	JS Interpreter on Go
Anko	92,579ms	18ms	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

Documentation

Index

• Variables

Variables

var (
	// MaxStringLen is the maximum byte-length for string value.
	// Note this limit applies to all compiler/VM instances in the process.
	MaxStringLen = 2147483647

	// MaxBytesLen is the maximum length for bytes value.
	// Note this limit applies to all compiler/VM instances in the process.
	MaxBytesLen = 2147483647
)