lua

README

luago, makes lua be embedded easily

Lua is a powerful, efficient, lightweight, embeddable scripting language. For most of developers who are not familiar with C language, it is very tedious to call lua_pushxxx() and lua_pop() to make use of the power of Lua. Though there are some binding implementations of Lua for languages other than C, most of them inherit the methods of using API of Lua.

luago is a package wrapping Lua and making it a pragmatic embeddable language. With some helper functions provided by luago, calling Golang functions from Lua, or calling Lua functions from Golang are both very simple. So, with the help of luago, Lua can be embedded in Golang application easily.

Install

The package is fully go-getable, So, just type

go get github.com/rosbit/luago

to install.

Usage

1. Evaluates expressions

package main

import (
  lua "github.com/rosbit/luago"
  "fmt"
)

func main() {
  ctx, err := lua.NewContext()
  if err != nil {
    fmt.Printf("%v\n", err)
    return
  }

  if err = ctx.LoadString("res = a + b", map[string]interface{}{
     "a": 10,
     "b": 1,
  }); err == nil {
     res, _ := ctx.GetGlobal("res")
     fmt.Println("result is:", res)
  }
}

2. Go calls Lua function

Suppose there's a Lua file named a.lua like this:

function add(a, b)
    return a+b
end

one can call the Lua function add() in Go code like the following:

package main

import (
  lua "github.com/rosbit/luago"
  "fmt"
)

var add func(int, int)int

func main() {
  ctx, err := lua.NewContext()
  if err != nil {
     fmt.Printf("%v\n", err)
     return
  }

  if err = ctx.LoadFile("a.lua", nil); err != nil {
     fmt.Printf("%v\n", err)
     return
  }

  // method 1: bind Lua function with a golang var
  if err := ctx.BindFunc("add", &add); err != nil {
     fmt.Printf("%v\n", err)
     return
  }
  res := add(1, 2)

  // method 2: call Lua function using CallFunc
  res, err := ctx.CallFunc("add", 1, 2)
  if err != nil {
     fmt.Printf("%v\n", err)
     return
  }

  fmt.Println("result is:", res)
}

3. Lua calls Go function

Lua calling Go function is also easy. In the Go code, calling LoadFile with a map as env will make Golang functions as Lua global functions. There's the example:

package main

import "github.com/rosbit/luago"

// function to be called by Lua
func adder(a1 float64, a2 float64) float64 {
    return a1 + a2
}

func main() {
  ctx, err := lua.NewContext()
  if err != nil {
      fmt.Printf("%v\n", err)
      return
  }

  if err := ctx.LoadFile("b.lua", map[string]interface{}{
      "adder": adder,
  })  // b.lua containing code calling "adder"
}

In Lua code, one can call the registered function directly. There's the example b.lua.

r = adder(1, 100)   -- the function "adder" is implemented in Go
print(r)

Status

The package is not fully tested, so be careful.

Contribution

Pull requests are welcome! Also, if you want to discuss something send a pull request with proposal and changes.

Convention: fork the repository and make changes on your fork in a feature branch.

Documentation

Index

• func InitCache()
• func InitPtrStore() (getPtrStore fnGetPtrStore, delPtrStore fnDelPtrStore)
• type LuaContext
  • func LoadFileFromCache(path string, vars map[string]interface{}) (ctx *LuaContext, existing bool, err error)
  • func NewContext() (*LuaContext, error)
  • func (ctx *LuaContext) BindFunc(funcName string, funcVarPtr interface{}) (err error)
  • func (ctx *LuaContext) BindFuncs(funcName2FuncVarPtr map[string]interface{}) (err error)
  • func (ctx *LuaContext) CallFunc(funcName string, args ...interface{}) (res interface{}, err error)
  • func (ctx *LuaContext) GetGlobal(name string) (res interface{}, err error)
  • func (ctx *LuaContext) LoadFile(scriptFile string, env map[string]interface{}) (err error)
  • func (ctx *LuaContext) LoadScript(script string, env map[string]interface{}) (err error)

Functions

func InitCache

func InitCache()

func InitPtrStore

func InitPtrStore() (getPtrStore fnGetPtrStore, delPtrStore fnDelPtrStore)

Types

type LuaContext

type LuaContext struct {
	// contains filtered or unexported fields
}

func LoadFileFromCache

func LoadFileFromCache(path string, vars map[string]interface{}) (ctx *LuaContext, existing bool, err error)

func NewContext

func NewContext() (*LuaContext, error)

func (*LuaContext) BindFunc

func (ctx *LuaContext) BindFunc(funcName string, funcVarPtr interface{}) (err error)

bind a var of golang func with a JS function name, so calling JS function is just calling the related golang func. @param funcVarPtr in format `var funcVar func(....) ...; funcVarPtr = &funcVar`

func (*LuaContext) BindFuncs

func (ctx *LuaContext) BindFuncs(funcName2FuncVarPtr map[string]interface{}) (err error)

func (*LuaContext) CallFunc

func (ctx *LuaContext) CallFunc(funcName string, args ...interface{}) (res interface{}, err error)

func (*LuaContext) GetGlobal

func (ctx *LuaContext) GetGlobal(name string) (res interface{}, err error)

func (*LuaContext) LoadFile

func (ctx *LuaContext) LoadFile(scriptFile string, env map[string]interface{}) (err error)

func (*LuaContext) LoadScript

func (ctx *LuaContext) LoadScript(script string, env map[string]interface{}) (err error)