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Published: Jan 22, 2023 License: MIT Imports: 24 Imported by: 1,302


GopherLua: VM and compiler for Lua in Go.

.. image::

.. image::

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.. image::
    :alt: Join the chat at


GopherLua is a Lua5.1(+ `goto` statement in Lua5.2) VM and compiler written in Go. GopherLua has a same goal
with Lua: **Be a scripting language with extensible semantics** . It provides
Go APIs that allow you to easily embed a scripting language to your Go host

.. contents::
   :depth: 1

Design principle

- Be a scripting language with extensible semantics.
- User-friendly Go API
    - The stack based API like the one used in the original Lua
      implementation will cause a performance improvements in GopherLua
      (It will reduce memory allocations and concrete type <-> interface conversions).
      GopherLua API is **not** the stack based API.
      GopherLua give preference to the user-friendliness over the performance.

How about performance?
GopherLua is not fast but not too slow, I think.

GopherLua has almost equivalent ( or little bit better ) performance as Python3 on micro benchmarks.

There are some benchmarks on the `wiki page <>`_ .


.. code-block:: bash

   go get

GopherLua supports >= Go1.9.

GopherLua APIs perform in much the same way as Lua, **but the stack is used only
for passing arguments and receiving returned values.**

GopherLua supports channel operations. See **"Goroutines"** section.

Import a package.

.. code-block:: go

   import (

Run scripts in the VM.

.. code-block:: go

   L := lua.NewState()
   defer L.Close()
   if err := L.DoString(`print("hello")`); err != nil {

.. code-block:: go

   L := lua.NewState()
   defer L.Close()
   if err := L.DoFile("hello.lua"); err != nil {

Refer to `Lua Reference Manual <>`_ and `Go doc <>`_ for further information.

Note that elements that are not commented in `Go doc <>`_ equivalent to `Lua Reference Manual <>`_ , except GopherLua uses objects instead of Lua stack indices.

Data model
All data in a GopherLua program is an ``LValue`` . ``LValue`` is an interface
type that has following methods.

- ``String() string``
- ``Type() LValueType``

Objects implement an LValue interface are

================ ========================= ================== =======================
 Type name        Go type                   Type() value       Constants
================ ========================= ================== =======================
 ``LNilType``      (constants)              ``LTNil``          ``LNil``
 ``LBool``         (constants)              ``LTBool``         ``LTrue``, ``LFalse``
 ``LNumber``        float64                 ``LTNumber``       ``-``
 ``LString``        string                  ``LTString``       ``-``
 ``LFunction``      struct pointer          ``LTFunction``     ``-``
 ``LUserData``      struct pointer          ``LTUserData``     ``-``
 ``LState``         struct pointer          ``LTThread``       ``-``
 ``LTable``         struct pointer          ``LTTable``        ``-``
 ``LChannel``       chan LValue             ``LTChannel``      ``-``
================ ========================= ================== =======================

You can test an object type in Go way(type assertion) or using a ``Type()`` value.

.. code-block:: go

   lv := L.Get(-1) // get the value at the top of the stack
   if str, ok := lv.(lua.LString); ok {
       // lv is LString
   if lv.Type() != lua.LTString {
       panic("string required.")

.. code-block:: go

   lv := L.Get(-1) // get the value at the top of the stack
   if tbl, ok := lv.(*lua.LTable); ok {
       // lv is LTable

Note that ``LBool`` , ``LNumber`` , ``LString`` is not a pointer.

To test ``LNilType`` and ``LBool``, You **must** use pre-defined constants.

.. code-block:: go

   lv := L.Get(-1) // get the value at the top of the stack

   if lv == lua.LTrue { // correct

   if bl, ok := lv.(lua.LBool); ok && bool(bl) { // wrong

In Lua, both ``nil`` and ``false`` make a condition false. ``LVIsFalse`` and ``LVAsBool`` implement this specification.

.. code-block:: go

   lv := L.Get(-1) // get the value at the top of the stack
   if lua.LVIsFalse(lv) { // lv is nil or false

   if lua.LVAsBool(lv) { // lv is neither nil nor false

Objects that based on go structs(``LFunction``. ``LUserData``, ``LTable``)
have some public methods and fields. You can use these methods and fields for
performance and debugging, but there are some limitations.

- Metatable does not work.
- No error handlings.

Callstack & Registry size
The size of an ``LState``'s callstack controls the maximum call depth for Lua functions within a script (Go function calls do not count).

The registry of an ``LState`` implements stack storage for calling functions (both Lua and Go functions) and also for temporary variables in expressions. Its storage requirements will increase with callstack usage and also with code complexity.

Both the registry and the callstack can be set to either a fixed size or to auto size.

When you have a large number of ``LStates`` instantiated in a process, it's worth taking the time to tune the registry and callstack options.


The registry can have an initial size, a maximum size and a step size configured on a per ``LState`` basis. This will allow the registry to grow as needed. It will not shrink again after growing.

.. code-block:: go

    L := lua.NewState(lua.Options{
       RegistrySize: 1024 * 20,         // this is the initial size of the registry
       RegistryMaxSize: 1024 * 80,      // this is the maximum size that the registry can grow to. If set to `0` (the default) then the registry will not auto grow
       RegistryGrowStep: 32,            // this is how much to step up the registry by each time it runs out of space. The default is `32`.
   defer L.Close()

A registry which is too small for a given script will ultimately result in a panic. A registry which is too big will waste memory (which can be significant if many ``LStates`` are instantiated).
Auto growing registries incur a small performance hit at the point they are resized but will not otherwise affect performance.


The callstack can operate in two different modes, fixed or auto size.
A fixed size callstack has the highest performance and has a fixed memory overhead.
An auto sizing callstack will allocate and release callstack pages on demand which will ensure the minimum amount of memory is in use at any time. The downside is it will incur a small performance impact every time a new page of callframes is allocated.
By default an ``LState`` will allocate and free callstack frames in pages of 8, so the allocation overhead is not incurred on every function call. It is very likely that the performance impact of an auto resizing callstack will be negligible for most use cases.

.. code-block:: go

    L := lua.NewState(lua.Options{
        CallStackSize: 120,                 // this is the maximum callstack size of this LState
        MinimizeStackMemory: true,          // Defaults to `false` if not specified. If set, the callstack will auto grow and shrink as needed up to a max of `CallStackSize`. If not set, the callstack will be fixed at `CallStackSize`.
   defer L.Close()

Option defaults

The above examples show how to customize the callstack and registry size on a per ``LState`` basis. You can also adjust some defaults for when options are not specified by altering the values of ``lua.RegistrySize``, ``lua.RegistryGrowStep`` and ``lua.CallStackSize``.

An ``LState`` object that has been created by ``*LState#NewThread()`` inherits the callstack & registry size from the parent ``LState`` object.

Miscellaneous lua.NewState options
- **Options.SkipOpenLibs bool(default false)**
    - By default, GopherLua opens all built-in libraries when new LState is created.
    - You can skip this behaviour by setting this to ``true`` .
    - Using the various `OpenXXX(L *LState) int` functions you can open only those libraries that you require, for an example see below.
- **Options.IncludeGoStackTrace bool(default false)**
    - By default, GopherLua does not show Go stack traces when panics occur.
    - You can get Go stack traces by setting this to ``true`` .


Refer to `Lua Reference Manual <>`_ and `Go doc(LState methods) <>`_ for further information.

Calling Go from Lua

.. code-block:: go

   func Double(L *lua.LState) int {
       lv := L.ToInt(1)             /* get argument */
       L.Push(lua.LNumber(lv * 2)) /* push result */
       return 1                     /* number of results */

   func main() {
       L := lua.NewState()
       defer L.Close()
       L.SetGlobal("double", L.NewFunction(Double)) /* Original lua_setglobal uses stack... */

.. code-block:: lua

   print(double(20)) -- > "40"

Any function registered with GopherLua is a ``lua.LGFunction``, defined in ``value.go``

.. code-block:: go

   type LGFunction func(*LState) int

Working with coroutines.

.. code-block:: go

   co, _ := L.NewThread() /* create a new thread */
   fn := L.GetGlobal("coro").(*lua.LFunction) /* get function from lua */
   for {
       st, err, values := L.Resume(co, fn)
       if st == lua.ResumeError {
           fmt.Println("yield break(error)")

       for i, lv := range values {
           fmt.Printf("%v : %v\n", i, lv)

       if st == lua.ResumeOK {
           fmt.Println("yield break(ok)")

Opening a subset of builtin modules

The following demonstrates how to open a subset of the built-in modules in Lua, say for example to avoid enabling modules with access to local files or system calls.


.. code-block:: go

    func main() {
        L := lua.NewState(lua.Options{SkipOpenLibs: true})
        defer L.Close()
        for _, pair := range []struct {
            n string
            f lua.LGFunction
            {lua.LoadLibName, lua.OpenPackage}, // Must be first
            {lua.BaseLibName, lua.OpenBase},
            {lua.TabLibName, lua.OpenTable},
        } {
            if err := L.CallByParam(lua.P{
                Fn:      L.NewFunction(pair.f),
                NRet:    0,
                Protect: true,
            }, lua.LString(pair.n)); err != nil {
        if err := L.DoFile("main.lua"); err != nil {

Creating a module by Go


.. code-block:: go

    package mymodule

    import (

    func Loader(L *lua.LState) int {
        // register functions to the table
        mod := L.SetFuncs(L.NewTable(), exports)
        // register other stuff
        L.SetField(mod, "name", lua.LString("value"))

        // returns the module
        return 1

    var exports = map[string]lua.LGFunction{
        "myfunc": myfunc,

    func myfunc(L *lua.LState) int {
        return 0


.. code-block:: go

    package main

    import (

    func main() {
        L := lua.NewState()
        defer L.Close()
        L.PreloadModule("mymodule", mymodule.Loader)
        if err := L.DoFile("main.lua"); err != nil {


.. code-block:: lua

    local m = require("mymodule")

Calling Lua from Go

.. code-block:: go

   L := lua.NewState()
   defer L.Close()
   if err := L.DoFile("double.lua"); err != nil {
   if err := L.CallByParam(lua.P{
       Fn: L.GetGlobal("double"),
       NRet: 1,
       Protect: true,
       }, lua.LNumber(10)); err != nil {
   ret := L.Get(-1) // returned value
   L.Pop(1)  // remove received value

If ``Protect`` is false, GopherLua will panic instead of returning an ``error`` value.

User-Defined types
You can extend GopherLua with new types written in Go.
``LUserData`` is provided for this purpose.

.. code-block:: go

    type Person struct {
        Name string

    const luaPersonTypeName = "person"

    // Registers my person type to given L.
    func registerPersonType(L *lua.LState) {
        mt := L.NewTypeMetatable(luaPersonTypeName)
        L.SetGlobal("person", mt)
        // static attributes
        L.SetField(mt, "new", L.NewFunction(newPerson))
        // methods
        L.SetField(mt, "__index", L.SetFuncs(L.NewTable(), personMethods))

    // Constructor
    func newPerson(L *lua.LState) int {
        person := &Person{L.CheckString(1)}
        ud := L.NewUserData()
        ud.Value = person
        L.SetMetatable(ud, L.GetTypeMetatable(luaPersonTypeName))
        return 1

    // Checks whether the first lua argument is a *LUserData with *Person and returns this *Person.
    func checkPerson(L *lua.LState) *Person {
        ud := L.CheckUserData(1)
        if v, ok := ud.Value.(*Person); ok {
            return v
        L.ArgError(1, "person expected")
        return nil

    var personMethods = map[string]lua.LGFunction{
        "name": personGetSetName,

    // Getter and setter for the Person#Name
    func personGetSetName(L *lua.LState) int {
        p := checkPerson(L)
        if L.GetTop() == 2 {
            p.Name = L.CheckString(2)
            return 0
        return 1

    func main() {
        L := lua.NewState()
        defer L.Close()
        if err := L.DoString(`
            p ="Steeve")
            print(p:name()) -- "Steeve"
            print(p:name()) -- "Alice"
        `); err != nil {

Terminating a running LState
GopherLua supports the `Go Concurrency Patterns: Context <>`_ .

.. code-block:: go

    L := lua.NewState()
    defer L.Close()
    ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
    defer cancel()
    // set the context to our LState
    err := L.DoString(`
      local clock = os.clock
      function sleep(n)  -- seconds
        local t0 = clock()
        while clock() - t0 <= n do end
    // err.Error() contains "context deadline exceeded"

With coroutines

.. code-block:: go

	L := lua.NewState()
	defer L.Close()
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	    function coro()
		  local i = 0
		  while true do
			i = i+1
		  return i
	co, cocancel := L.NewThread()
	defer cocancel()
	fn := L.GetGlobal("coro").(*LFunction)

	_, err, values := L.Resume(co, fn) // err is nil

	cancel() // cancel the parent context

	_, err, values = L.Resume(co, fn) // err is NOT nil : child context was canceled

**Note that using a context causes performance degradation.**

.. code-block::

    time ./glua-with-context.exe fib.lua
    0.01s user 0.11s system 1% cpu 7.505 total

    time ./glua-without-context.exe fib.lua
    0.01s user 0.01s system 0% cpu 5.306 total

Sharing Lua byte code between LStates
Calling ``DoFile`` will load a Lua script, compile it to byte code and run the byte code in a ``LState``.

If you have multiple ``LStates`` which are all required to run the same script, you can share the byte code between them,
which will save on memory.
Sharing byte code is safe as it is read only and cannot be altered by lua scripts.

.. code-block:: go

    // CompileLua reads the passed lua file from disk and compiles it.
    func CompileLua(filePath string) (*lua.FunctionProto, error) {
        file, err := os.Open(filePath)
        defer file.Close()
        if err != nil {
            return nil, err
        reader := bufio.NewReader(file)
        chunk, err := parse.Parse(reader, filePath)
        if err != nil {
            return nil, err
        proto, err := lua.Compile(chunk, filePath)
        if err != nil {
            return nil, err
        return proto, nil

    // DoCompiledFile takes a FunctionProto, as returned by CompileLua, and runs it in the LState. It is equivalent
    // to calling DoFile on the LState with the original source file.
    func DoCompiledFile(L *lua.LState, proto *lua.FunctionProto) error {
        lfunc := L.NewFunctionFromProto(proto)
        return L.PCall(0, lua.MultRet, nil)

    // Example shows how to share the compiled byte code from a lua script between multiple VMs.
    func Example() {
        codeToShare := CompileLua("mylua.lua")
        a := lua.NewState()
        b := lua.NewState()
        c := lua.NewState()
        DoCompiledFile(a, codeToShare)
        DoCompiledFile(b, codeToShare)
        DoCompiledFile(c, codeToShare)

The ``LState`` is not goroutine-safe. It is recommended to use one LState per goroutine and communicate between goroutines by using channels.

Channels are represented by ``channel`` objects in GopherLua. And a ``channel`` table provides functions for performing channel operations.

Some objects can not be sent over channels due to having non-goroutine-safe objects inside itself.

- a thread(state)
- a function
- an userdata
- a table with a metatable

You **must not** send these objects from Go APIs to channels.

.. code-block:: go

    func receiver(ch, quit chan lua.LValue) {
        L := lua.NewState()
        defer L.Close()
        L.SetGlobal("ch", lua.LChannel(ch))
        L.SetGlobal("quit", lua.LChannel(quit))
        if err := L.DoString(`
        local exit = false
        while not exit do

            {"|<-", ch, function(ok, v)
              if not ok then
                print("channel closed")
                exit = true
                print("received:", v)
            {"|<-", quit, function(ok, v)
                exit = true
      `); err != nil {

    func sender(ch, quit chan lua.LValue) {
        L := lua.NewState()
        defer L.Close()
        L.SetGlobal("ch", lua.LChannel(ch))
        L.SetGlobal("quit", lua.LChannel(quit))
        if err := L.DoString(`
      `); err != nil {
        ch <- lua.LString("3")
        quit <- lua.LTrue

    func main() {
        ch := make(chan lua.LValue)
        quit := make(chan lua.LValue)
        go receiver(ch, quit)
        go sender(ch, quit)
        time.Sleep(3 * time.Second)


``ToChannel``, ``CheckChannel``, ``OptChannel`` are available.

Refer to `Go doc(LState methods) <>`_ for further information.


- **channel.make([buf:int]) -> ch:channel**
    - Create new channel that has a buffer size of ``buf``. By default, ``buf`` is 0.

- ** [, case:table, case:table ...]) -> {index:int, recv:any, ok}**
    - Same as the ``select`` statement in Go. It returns the index of the chosen case and, if that
      case was a receive operation, the value received and a boolean indicating whether the channel has been closed.
    - ``case`` is a table that outlined below.
        - receiving: `{"|<-", ch:channel [, handler:func(ok, data:any)]}`
        - sending: `{"<-|", ch:channel, data:any [, handler:func(data:any)]}`
        - default: `{"default" [, handler:func()]}`

```` examples:

.. code-block:: lua

    local idx, recv, ok =
      {"|<-", ch1},
      {"|<-", ch2}
    if not ok then
    elseif idx == 1 then -- received from ch1
    elseif idx == 2 then -- received from ch2

.. code-block:: lua
      {"|<-", ch1, function(ok, data)
        print(ok, data)
      {"<-|", ch2, "value", function(data)
      {"default", function()
        print("default action")

- **channel:send(data:any)**
    - Send ``data`` over the channel.
- **channel:receive() -> ok:bool, data:any**
    - Receive some data over the channel.
- **channel:close()**
    - Close the channel.

The LState pool pattern
To create per-thread LState instances, You can use the ``sync.Pool`` like mechanism.

.. code-block:: go

    type lStatePool struct {
        m     sync.Mutex
        saved []*lua.LState

    func (pl *lStatePool) Get() *lua.LState {
        defer pl.m.Unlock()
        n := len(pl.saved)
        if n == 0 {
            return pl.New()
        x := pl.saved[n-1]
        pl.saved = pl.saved[0 : n-1]
        return x

    func (pl *lStatePool) New() *lua.LState {
        L := lua.NewState()
        // setting the L up here.
        // load scripts, set global variables, share channels, etc...
        return L

    func (pl *lStatePool) Put(L *lua.LState) {
        defer pl.m.Unlock()
        pl.saved = append(pl.saved, L)

    func (pl *lStatePool) Shutdown() {
        for _, L := range pl.saved {

    // Global LState pool
    var luaPool = &lStatePool{
        saved: make([]*lua.LState, 0, 4),

Now, you can get per-thread LState objects from the ``luaPool`` .

.. code-block:: go

    func MyWorker() {
       L := luaPool.Get()
       defer luaPool.Put(L)
       /* your code here */

    func main() {
        defer luaPool.Shutdown()
        go MyWorker()
        go MyWorker()
        /* etc... */

Differences between Lua and GopherLua

- GopherLua supports channel operations.
    - GopherLua has a type named ``channel``.
    - The ``channel`` table provides functions for performing channel operations.

Unsupported functions

- ``string.dump``
- ``os.setlocale``
- ``lua_Debug.namewhat``
- ``package.loadlib``
- debug hooks

Miscellaneous notes

- ``collectgarbage`` does not take any arguments and runs the garbage collector for the entire Go program.
- ``file:setvbuf`` does not support a line buffering.
- Daylight saving time is not supported.
- GopherLua has a function to set an environment variable : ``os.setenv(name, value)``
- GopherLua support ``goto`` and ``::label::`` statement in Lua5.2.
    - `goto` is a keyword and not a valid variable name.

Standalone interpreter
Lua has an interpreter called ``lua`` . GopherLua has an interpreter called ``glua`` .

.. code-block:: bash

   go get

``glua`` has same options as ``lua`` .

How to Contribute
See `Guidlines for contributors <>`_ .

Libraries for GopherLua

- `gopher-luar <>`_ : Simplifies data passing to and from gopher-lua
- `gluamapper <>`_ : Mapping a Lua table to a Go struct
- `gluare <>`_ : Regular expressions for gopher-lua
- `gluahttp <>`_ : HTTP request module for gopher-lua
- `gopher-json <>`_ : A simple JSON encoder/decoder for gopher-lua
- `gluayaml <>`_ : Yaml parser for gopher-lua
- `glua-lfs <>`_ : Partially implements the luafilesystem module for gopher-lua
- `gluaurl <>`_ : A url parser/builder module for gopher-lua
- `gluahttpscrape <>`_ : A simple HTML scraper module for gopher-lua
- `gluaxmlpath <>`_ : An xmlpath module for gopher-lua
- `gmoonscript <>`_ : Moonscript Compiler for the Gopher Lua VM
- `loguago <>`_ : Zerolog wrapper for Gopher-Lua
- `gluacrypto <>`_ : A native Go implementation of crypto library for the GopherLua VM.
- `gluasql <>`_ : A native Go implementation of SQL client for the GopherLua VM.
- `purr <>`_ : A http mock testing tool.
- `vadv/gopher-lua-libs <>`_ : Some usefull libraries for GopherLua VM.
- `gluaperiphery <>`_ : A periphery library for the GopherLua VM (GPIO, SPI, I2C, MMIO, and Serial peripheral I/O for Linux).
- `glua-async <>`_ : An async/await implement for gopher-lua.
- `gopherlua-debugger <>`_ : A debugger for gopher-lua
- `gluamahonia <>`_ : An encoding converter for gopher-lua



Yusuke Inuzuka



GopherLua: VM and compiler for Lua in Go



View Source
const (
	VarArgHasArg   uint8 = 1
	VarArgIsVarArg uint8 = 2
	VarArgNeedsArg uint8 = 4
View Source
const (
	// BaseLibName is here for consistency; the base functions have no namespace/library.
	BaseLibName = ""
	// LoadLibName is here for consistency; the loading system has no namespace/library.
	LoadLibName = "package"
	// TabLibName is the name of the table Library.
	TabLibName = "table"
	// IoLibName is the name of the io Library.
	IoLibName = "io"
	// OsLibName is the name of the os Library.
	OsLibName = "os"
	// StringLibName is the name of the string Library.
	StringLibName = "string"
	// MathLibName is the name of the math Library.
	MathLibName = "math"
	// DebugLibName is the name of the debug Library.
	DebugLibName = "debug"
	// ChannelLibName is the name of the channel Library.
	ChannelLibName = "channel"
	// CoroutineLibName is the name of the coroutine Library.
	CoroutineLibName = "coroutine"
View Source
const (
	OP_MOVE     int = iota /*      A B     R(A) := R(B)                            */
	OP_MOVEN               /*      A B     R(A) := R(B); followed by R(C) MOVE ops */
	OP_LOADK               /*     A Bx    R(A) := Kst(Bx)                          */
	OP_LOADBOOL            /*  A B C   R(A) := (Bool)B; if (C) pc++                */
	OP_LOADNIL             /*   A B     R(A) := ... := R(B) := nil                 */
	OP_GETUPVAL            /*  A B     R(A) := UpValue[B]                          */

	OP_GETGLOBAL  /* A Bx    R(A) := Gbl[Kst(Bx)]                            */
	OP_GETTABLE   /*  A B C   R(A) := R(B)[RK(C)]                             */
	OP_GETTABLEKS /*  A B C   R(A) := R(B)[RK(C)] ; RK(C) is constant string */

	OP_SETGLOBAL  /* A Bx    Gbl[Kst(Bx)] := R(A)                            */
	OP_SETUPVAL   /*  A B     UpValue[B] := R(A)                              */
	OP_SETTABLE   /*  A B C   R(A)[RK(B)] := RK(C)                            */
	OP_SETTABLEKS /*  A B C   R(A)[RK(B)] := RK(C) ; RK(B) is constant string */

	OP_NEWTABLE /*  A B C   R(A) := {} (size = BC)                         */

	OP_SELF /*      A B C   R(A+1) := R(B); R(A) := R(B)[RK(C)]             */

	OP_ADD /*       A B C   R(A) := RK(B) + RK(C)                           */
	OP_SUB /*       A B C   R(A) := RK(B) - RK(C)                           */
	OP_MUL /*       A B C   R(A) := RK(B) * RK(C)                           */
	OP_DIV /*       A B C   R(A) := RK(B) / RK(C)                           */
	OP_MOD /*       A B C   R(A) := RK(B) % RK(C)                           */
	OP_POW /*       A B C   R(A) := RK(B) ^ RK(C)                           */
	OP_UNM /*       A B     R(A) := -R(B)                                   */
	OP_NOT /*       A B     R(A) := not R(B)                                */
	OP_LEN /*       A B     R(A) := length of R(B)                          */

	OP_CONCAT /*    A B C   R(A) := R(B).. ... ..R(C)                       */

	OP_JMP /*       sBx     pc+=sBx                                 */

	OP_EQ /*        A B C   if ((RK(B) == RK(C)) ~= A) then pc++            */
	OP_LT /*        A B C   if ((RK(B) <  RK(C)) ~= A) then pc++            */
	OP_LE /*        A B C   if ((RK(B) <= RK(C)) ~= A) then pc++            */

	OP_TEST    /*      A C     if not (R(A) <=> C) then pc++                   */
	OP_TESTSET /*   A B C   if (R(B) <=> C) then R(A) := R(B) else pc++     */

	OP_CALL     /*      A B C   R(A) ... R(A+C-2) := R(A)(R(A+1) ... R(A+B-1)) */
	OP_TAILCALL /*  A B C   return R(A)(R(A+1) ... R(A+B-1))              */
	OP_RETURN   /*    A B     return R(A) ... R(A+B-2)      (see note)      */

	OP_FORLOOP /*   A sBx   R(A)+=R(A+2);
	     if R(A) <?= R(A+1) then { pc+=sBx; R(A+3)=R(A) }*/
	OP_FORPREP /*   A sBx   R(A)-=R(A+2); pc+=sBx                           */

	OP_TFORLOOP /*  A C     R(A+3) ... R(A+3+C) := R(A)(R(A+1) R(A+2));
	    if R(A+3) ~= nil then { pc++; R(A+2)=R(A+3); }  */
	OP_SETLIST /*   A B C   R(A)[(C-1)*FPF+i] := R(A+i) 1 <= i <= B        */

	OP_CLOSE   /*     A       close all variables in the stack up to (>=) R(A)*/
	OP_CLOSURE /*   A Bx    R(A) := closure(KPROTO[Bx] R(A) ... R(A+n))  */

	OP_VARARG /*     A B     R(A) R(A+1) ... R(A+B-1) = vararg            */

	OP_NOP /* NOP */
View Source
const EnvironIndex = -10001
View Source
const FramesPerSegment = 8

FramesPerSegment should be a power of 2 constant for performance reasons. It will allow the go compiler to change the divs and mods into bitshifts. Max is 256 due to current use of uint8 to count how many frames in a segment are used.

View Source
const GlobalsIndex = -10002
View Source
const LNumberBit = 64
View Source
const LNumberScanFormat = "%f"
View Source
const LuaVersion = "Lua 5.1"
View Source
const MultRet = -1
View Source
const PackageAuthors = "Yusuke Inuzuka"
View Source
const PackageCopyRight = PackageName + " " + PackageVersion + " Copyright (C) 2015 -2017 " + PackageAuthors
View Source
const PackageName = "GopherLua"
View Source
const PackageVersion = "0.1"
View Source
const RegistryIndex = -10000


View Source
var CallStackSize = 256
View Source
var CompatVarArg = true
View Source
var FieldsPerFlush = 50
View Source
var LFalse = LBool(false)
View Source
var LNil = LValue(&LNilType{})
View Source
var LTrue = LBool(true)
View Source
var LuaDirSep string
View Source
var LuaExecDir = "!"
View Source
var LuaIgMark = "-"
View Source
var LuaLDir string
View Source
var LuaOS string
View Source
var LuaPath = "LUA_PATH"
View Source
var LuaPathDefault string
View Source
var LuaPathMark = "?"
View Source
var LuaPathSep = ";"
View Source
var MaxArrayIndex = 67108864
View Source
var MaxTableGetLoop = 100
View Source
var RegistryGrowStep = 32
View Source
var RegistrySize = 256 * 20


func LVAsBool

func LVAsBool(v LValue) bool

LVIsFalse returns false if a given LValue is a nil or false otherwise true.

func LVAsString

func LVAsString(v LValue) string

LVAsString returns string representation of a given LValue if the LValue is a string or number, otherwise an empty string.

func LVCanConvToString

func LVCanConvToString(v LValue) bool

LVCanConvToString returns true if a given LValue is a string or number otherwise false.

func LVIsFalse

func LVIsFalse(v LValue) bool

LVIsFalse returns true if a given LValue is a nil or false otherwise false.

func OpenBase

func OpenBase(L *LState) int

func OpenChannel

func OpenChannel(L *LState) int

func OpenCoroutine

func OpenCoroutine(L *LState) int

func OpenDebug

func OpenDebug(L *LState) int

func OpenIo

func OpenIo(L *LState) int

func OpenMath

func OpenMath(L *LState) int

func OpenOs

func OpenOs(L *LState) int

func OpenPackage

func OpenPackage(L *LState) int

func OpenString

func OpenString(L *LState) int

func OpenTable

func OpenTable(L *LState) int

func UpvalueIndex

func UpvalueIndex(i int) int


type ApiError

type ApiError struct {
	Type       ApiErrorType
	Object     LValue
	StackTrace string
	// Underlying error. This attribute is set only if the Type is ApiErrorFile or ApiErrorSyntax
	Cause error

func (*ApiError) Error

func (e *ApiError) Error() string

type ApiErrorType

type ApiErrorType int
const (
	ApiErrorSyntax ApiErrorType = iota

type CompileError

type CompileError struct {
	Line    int
	Message string
	// contains filtered or unexported fields

func (*CompileError) Error

func (e *CompileError) Error() string

type DbgCall

type DbgCall struct {
	Name string
	Pc   int

type DbgLocalInfo

type DbgLocalInfo struct {
	Name    string
	StartPc int
	EndPc   int

type Debug

type Debug struct {
	Name            string
	What            string
	Source          string
	CurrentLine     int
	NUpvalues       int
	LineDefined     int
	LastLineDefined int
	// contains filtered or unexported fields

type FunctionProto

type FunctionProto struct {
	SourceName         string
	LineDefined        int
	LastLineDefined    int
	NumUpvalues        uint8
	NumParameters      uint8
	IsVarArg           uint8
	NumUsedRegisters   uint8
	Code               []uint32
	Constants          []LValue
	FunctionPrototypes []*FunctionProto

	DbgSourcePositions []int
	DbgLocals          []*DbgLocalInfo
	DbgCalls           []DbgCall
	DbgUpvalues        []string
	// contains filtered or unexported fields

func Compile

func Compile(chunk []ast.Stmt, name string) (proto *FunctionProto, err error)

func (*FunctionProto) String

func (fp *FunctionProto) String() string

type Global

type Global struct {
	MainThread    *LState
	CurrentThread *LState
	Registry      *LTable
	Global        *LTable
	// contains filtered or unexported fields

type LBool

type LBool bool

func (LBool) String

func (bl LBool) String() string

func (LBool) Type

func (bl LBool) Type() LValueType

type LChannel

type LChannel chan LValue

func (LChannel) String

func (ch LChannel) String() string

func (LChannel) Type

func (ch LChannel) Type() LValueType

type LFunction

type LFunction struct {
	IsG       bool
	Env       *LTable
	Proto     *FunctionProto
	GFunction LGFunction
	Upvalues  []*Upvalue

func (*LFunction) LocalName

func (fn *LFunction) LocalName(regno, pc int) (string, bool)

func (*LFunction) String

func (fn *LFunction) String() string

func (*LFunction) Type

func (fn *LFunction) Type() LValueType

type LGFunction

type LGFunction func(*LState) int

type LNilType

type LNilType struct{}

func (*LNilType) String

func (nl *LNilType) String() string

func (*LNilType) Type

func (nl *LNilType) Type() LValueType

type LNumber

type LNumber float64

func LVAsNumber

func LVAsNumber(v LValue) LNumber

LVAsNumber tries to convert a given LValue to a number.

func (LNumber) Format

func (nm LNumber) Format(f fmt.State, c rune)

fmt.Formatter interface

func (LNumber) String

func (nm LNumber) String() string

func (LNumber) Type

func (nm LNumber) Type() LValueType

type LState

type LState struct {
	G       *Global
	Parent  *LState
	Env     *LTable
	Panic   func(*LState)
	Dead    bool
	Options Options
	// contains filtered or unexported fields

func NewState

func NewState(opts ...Options) *LState

func (*LState) ArgError

func (ls *LState) ArgError(n int, message string)

func (*LState) Call

func (ls *LState) Call(nargs, nret int)

func (*LState) CallByParam

func (ls *LState) CallByParam(cp P, args ...LValue) error

func (*LState) CallMeta

func (ls *LState) CallMeta(obj LValue, event string) LValue

func (*LState) CheckAny

func (ls *LState) CheckAny(n int) LValue

func (*LState) CheckBool

func (ls *LState) CheckBool(n int) bool

func (*LState) CheckChannel

func (ls *LState) CheckChannel(n int) chan LValue

Checks whether the given index is an LChannel and returns this channel.

func (*LState) CheckFunction

func (ls *LState) CheckFunction(n int) *LFunction

func (*LState) CheckInt

func (ls *LState) CheckInt(n int) int

func (*LState) CheckInt64

func (ls *LState) CheckInt64(n int) int64

func (*LState) CheckNumber

func (ls *LState) CheckNumber(n int) LNumber

func (*LState) CheckOption

func (ls *LState) CheckOption(n int, options []string) int

func (*LState) CheckString

func (ls *LState) CheckString(n int) string

func (*LState) CheckTable

func (ls *LState) CheckTable(n int) *LTable

func (*LState) CheckThread

func (ls *LState) CheckThread(n int) *LState

func (*LState) CheckType

func (ls *LState) CheckType(n int, typ LValueType)

func (*LState) CheckTypes

func (ls *LState) CheckTypes(n int, typs ...LValueType)

func (*LState) CheckUserData

func (ls *LState) CheckUserData(n int) *LUserData

func (*LState) Close

func (ls *LState) Close()

func (*LState) Concat

func (ls *LState) Concat(values ...LValue) string

func (*LState) Context

func (ls *LState) Context() context.Context

Context returns the LState's context. To change the context, use WithContext.

func (*LState) CreateTable

func (ls *LState) CreateTable(acap, hcap int) *LTable

func (*LState) DoFile

func (ls *LState) DoFile(path string) error

func (*LState) DoString

func (ls *LState) DoString(source string) error

func (*LState) Equal

func (ls *LState) Equal(lhs, rhs LValue) bool

func (*LState) Error

func (ls *LState) Error(lv LValue, level int)

This function is equivalent to lua_error( ).

func (*LState) FindTable

func (ls *LState) FindTable(obj *LTable, n string, size int) LValue

func (*LState) ForEach

func (ls *LState) ForEach(tb *LTable, cb func(LValue, LValue))

func (*LState) GPCall

func (ls *LState) GPCall(fn LGFunction, data LValue) error

func (*LState) Get

func (ls *LState) Get(idx int) LValue

func (*LState) GetFEnv

func (ls *LState) GetFEnv(obj LValue) LValue

func (*LState) GetField

func (ls *LState) GetField(obj LValue, skey string) LValue

func (*LState) GetGlobal

func (ls *LState) GetGlobal(name string) LValue

func (*LState) GetInfo

func (ls *LState) GetInfo(what string, dbg *Debug, fn LValue) (LValue, error)

func (*LState) GetLocal

func (ls *LState) GetLocal(dbg *Debug, no int) (string, LValue)

func (*LState) GetMetaField

func (ls *LState) GetMetaField(obj LValue, event string) LValue

func (*LState) GetMetatable

func (ls *LState) GetMetatable(obj LValue) LValue

func (*LState) GetStack

func (ls *LState) GetStack(level int) (*Debug, bool)

func (*LState) GetTable

func (ls *LState) GetTable(obj LValue, key LValue) LValue

func (*LState) GetTop

func (ls *LState) GetTop() int

func (*LState) GetTypeMetatable

func (ls *LState) GetTypeMetatable(typ string) LValue

func (*LState) GetUpvalue

func (ls *LState) GetUpvalue(fn *LFunction, no int) (string, LValue)

func (*LState) Insert

func (ls *LState) Insert(value LValue, index int)

func (*LState) IsClosed

func (ls *LState) IsClosed() bool

func (*LState) LessThan

func (ls *LState) LessThan(lhs, rhs LValue) bool

func (*LState) Load

func (ls *LState) Load(reader io.Reader, name string) (*LFunction, error)

func (*LState) LoadFile

func (ls *LState) LoadFile(path string) (*LFunction, error)

func (*LState) LoadString

func (ls *LState) LoadString(source string) (*LFunction, error)

func (*LState) NewClosure

func (ls *LState) NewClosure(fn LGFunction, upvalues ...LValue) *LFunction

func (*LState) NewFunction

func (ls *LState) NewFunction(fn LGFunction) *LFunction

func (*LState) NewFunctionFromProto

func (ls *LState) NewFunctionFromProto(proto *FunctionProto) *LFunction

func (*LState) NewTable

func (ls *LState) NewTable() *LTable

func (*LState) NewThread

func (ls *LState) NewThread() (*LState, context.CancelFunc)

NewThread returns a new LState that shares with the original state all global objects. If the original state has context.Context, the new state has a new child context of the original state and this function returns its cancel function.

func (*LState) NewTypeMetatable

func (ls *LState) NewTypeMetatable(typ string) *LTable

func (*LState) NewUserData

func (ls *LState) NewUserData() *LUserData

func (*LState) Next

func (ls *LState) Next(tb *LTable, key LValue) (LValue, LValue)

func (*LState) ObjLen

func (ls *LState) ObjLen(v1 LValue) int

func (*LState) OpenLibs

func (ls *LState) OpenLibs()

OpenLibs loads the built-in libraries. It is equivalent to running OpenLoad, then OpenBase, then iterating over the other OpenXXX functions in any order.

func (*LState) OptBool

func (ls *LState) OptBool(n int, d bool) bool

func (*LState) OptChannel

func (ls *LState) OptChannel(n int, ch chan LValue) chan LValue

If the given index is a LChannel, returns this channel. If this argument is absent or is nil, returns ch. Otherwise, raises an error.

func (*LState) OptFunction

func (ls *LState) OptFunction(n int, d *LFunction) *LFunction

func (*LState) OptInt

func (ls *LState) OptInt(n int, d int) int

func (*LState) OptInt64

func (ls *LState) OptInt64(n int, d int64) int64

func (*LState) OptNumber

func (ls *LState) OptNumber(n int, d LNumber) LNumber

func (*LState) OptString

func (ls *LState) OptString(n int, d string) string

func (*LState) OptTable

func (ls *LState) OptTable(n int, d *LTable) *LTable

func (*LState) OptUserData

func (ls *LState) OptUserData(n int, d *LUserData) *LUserData

func (*LState) PCall

func (ls *LState) PCall(nargs, nret int, errfunc *LFunction) (err error)

func (*LState) Pop

func (ls *LState) Pop(n int)

func (*LState) PreloadModule

func (ls *LState) PreloadModule(name string, loader LGFunction)

Set a module loader to the package.preload table.

func (*LState) Push

func (ls *LState) Push(value LValue)

func (*LState) RaiseError

func (ls *LState) RaiseError(format string, args ...interface{})

This function is equivalent to luaL_error( ).

func (*LState) RawEqual

func (ls *LState) RawEqual(lhs, rhs LValue) bool

func (*LState) RawGet

func (ls *LState) RawGet(tb *LTable, key LValue) LValue

func (*LState) RawGetInt

func (ls *LState) RawGetInt(tb *LTable, key int) LValue

func (*LState) RawSet

func (ls *LState) RawSet(tb *LTable, key LValue, value LValue)

func (*LState) RawSetInt

func (ls *LState) RawSetInt(tb *LTable, key int, value LValue)

func (*LState) Register

func (ls *LState) Register(name string, fn LGFunction)

func (*LState) RegisterModule

func (ls *LState) RegisterModule(name string, funcs map[string]LGFunction) LValue

func (*LState) Remove

func (ls *LState) Remove(index int)

func (*LState) RemoveCallerFrame

func (ls *LState) RemoveCallerFrame() *callFrame

RemoveCallerFrame removes the stack frame above the current stack frame. This is useful in tail calls. It returns the new current frame.

func (*LState) RemoveContext

func (ls *LState) RemoveContext() context.Context

RemoveContext removes the context associated with this LState and returns this context.

func (*LState) Replace

func (ls *LState) Replace(idx int, value LValue)

func (*LState) Resume

func (ls *LState) Resume(th *LState, fn *LFunction, args ...LValue) (ResumeState, error, []LValue)

func (*LState) SetContext

func (ls *LState) SetContext(ctx context.Context)

SetContext set a context ctx to this LState. The provided ctx must be non-nil.

func (*LState) SetFEnv

func (ls *LState) SetFEnv(obj LValue, env LValue)

func (*LState) SetField

func (ls *LState) SetField(obj LValue, key string, value LValue)

func (*LState) SetFuncs

func (ls *LState) SetFuncs(tb *LTable, funcs map[string]LGFunction, upvalues ...LValue) *LTable

func (*LState) SetGlobal

func (ls *LState) SetGlobal(name string, value LValue)

func (*LState) SetLocal

func (ls *LState) SetLocal(dbg *Debug, no int, lv LValue) string

func (*LState) SetMetatable

func (ls *LState) SetMetatable(obj LValue, mt LValue)

func (*LState) SetMx

func (ls *LState) SetMx(mx int)

Set maximum memory size. This function can only be called from the main thread.

func (*LState) SetTable

func (ls *LState) SetTable(obj LValue, key LValue, value LValue)

func (*LState) SetTop

func (ls *LState) SetTop(idx int)

func (*LState) SetUpvalue

func (ls *LState) SetUpvalue(fn *LFunction, no int, lv LValue) string

func (*LState) Status

func (ls *LState) Status(th *LState) string

func (*LState) String

func (ls *LState) String() string

func (*LState) ToBool

func (ls *LState) ToBool(n int) bool

func (*LState) ToChannel

func (ls *LState) ToChannel(n int) chan LValue

Converts the Lua value at the given acceptable index to the chan LValue.

func (*LState) ToFunction

func (ls *LState) ToFunction(n int) *LFunction

func (*LState) ToInt

func (ls *LState) ToInt(n int) int

func (*LState) ToInt64

func (ls *LState) ToInt64(n int) int64

func (*LState) ToNumber

func (ls *LState) ToNumber(n int) LNumber

func (*LState) ToString

func (ls *LState) ToString(n int) string

func (*LState) ToStringMeta

func (ls *LState) ToStringMeta(lv LValue) LValue

ToStringMeta returns string representation of given LValue. This method calls the `__tostring` meta method if defined.

func (*LState) ToTable

func (ls *LState) ToTable(n int) *LTable

func (*LState) ToThread

func (ls *LState) ToThread(n int) *LState

func (*LState) ToUserData

func (ls *LState) ToUserData(n int) *LUserData

func (*LState) Type

func (ls *LState) Type() LValueType

func (*LState) TypeError

func (ls *LState) TypeError(n int, typ LValueType)

func (*LState) Where

func (ls *LState) Where(level int) string

func (*LState) XMoveTo

func (ls *LState) XMoveTo(other *LState, n int)

func (*LState) Yield

func (ls *LState) Yield(values ...LValue) int

type LString

type LString string

func (LString) Format

func (st LString) Format(f fmt.State, c rune)

fmt.Formatter interface

func (LString) String

func (st LString) String() string

func (LString) Type

func (st LString) Type() LValueType

type LTable

type LTable struct {
	Metatable LValue
	// contains filtered or unexported fields

func (*LTable) Append

func (tb *LTable) Append(value LValue)

Append appends a given LValue to this LTable.

func (*LTable) ForEach

func (tb *LTable) ForEach(cb func(LValue, LValue))

ForEach iterates over this table of elements, yielding each in turn to a given function.

func (*LTable) Insert

func (tb *LTable) Insert(i int, value LValue)

Insert inserts a given LValue at position `i` in this table.

func (*LTable) Len

func (tb *LTable) Len() int

Len returns length of this LTable without using __len.

func (*LTable) MaxN

func (tb *LTable) MaxN() int

MaxN returns a maximum number key that nil value does not exist before it.

func (*LTable) Next

func (tb *LTable) Next(key LValue) (LValue, LValue)

This function is equivalent to lua_next ( ).

func (*LTable) RawGet

func (tb *LTable) RawGet(key LValue) LValue

RawGet returns an LValue associated with a given key without __index metamethod.

func (*LTable) RawGetH

func (tb *LTable) RawGetH(key LValue) LValue

RawGet returns an LValue associated with a given key without __index metamethod.

func (*LTable) RawGetInt

func (tb *LTable) RawGetInt(key int) LValue

RawGetInt returns an LValue at position `key` without __index metamethod.

func (*LTable) RawGetString

func (tb *LTable) RawGetString(key string) LValue

RawGetString returns an LValue associated with a given key without __index metamethod.

func (*LTable) RawSet

func (tb *LTable) RawSet(key LValue, value LValue)

RawSet sets a given LValue to a given index without the __newindex metamethod. It is recommended to use `RawSetString` or `RawSetInt` for performance if you already know the given LValue is a string or number.

func (*LTable) RawSetH

func (tb *LTable) RawSetH(key LValue, value LValue)

RawSetH sets a given LValue to a given index without the __newindex metamethod.

func (*LTable) RawSetInt

func (tb *LTable) RawSetInt(key int, value LValue)

RawSetInt sets a given LValue at a position `key` without the __newindex metamethod.

func (*LTable) RawSetString

func (tb *LTable) RawSetString(key string, value LValue)

RawSetString sets a given LValue to a given string index without the __newindex metamethod.

func (*LTable) Remove

func (tb *LTable) Remove(pos int) LValue

Remove removes from this table the element at a given position.

func (*LTable) String

func (tb *LTable) String() string

func (*LTable) Type

func (tb *LTable) Type() LValueType

type LUserData

type LUserData struct {
	Value     interface{}
	Env       *LTable
	Metatable LValue

func (*LUserData) String

func (ud *LUserData) String() string

func (*LUserData) Type

func (ud *LUserData) Type() LValueType

type LValue

type LValue interface {
	String() string
	Type() LValueType
	// contains filtered or unexported methods

type LValueType

type LValueType int
const (
	LTNil LValueType = iota

func (LValueType) String

func (vt LValueType) String() string

type Options

type Options struct {
	// Call stack size. This defaults to `lua.CallStackSize`.
	CallStackSize int
	// Data stack size. This defaults to `lua.RegistrySize`.
	RegistrySize int
	// Allow the registry to grow from the registry size specified up to a value of RegistryMaxSize. A value of 0
	// indicates no growth is permitted. The registry will not shrink again after any growth.
	RegistryMaxSize int
	// If growth is enabled, step up by an additional `RegistryGrowStep` each time to avoid having to resize too often.
	// This defaults to `lua.RegistryGrowStep`
	RegistryGrowStep int
	// Controls whether or not libraries are opened by default
	SkipOpenLibs bool
	// Tells whether a Go stacktrace should be included in a Lua stacktrace when panics occur.
	IncludeGoStackTrace bool
	// If `MinimizeStackMemory` is set, the call stack will be automatically grown or shrank up to a limit of
	// `CallStackSize` in order to minimize memory usage. This does incur a slight performance penalty.
	MinimizeStackMemory bool

Options is a configuration that is used to create a new LState.

type P

type P struct {
	Fn      LValue
	NRet    int
	Protect bool
	Handler *LFunction

type ResumeState

type ResumeState int
const (
	ResumeOK ResumeState = iota

type Upvalue

type Upvalue struct {
	// contains filtered or unexported fields

func (*Upvalue) Close

func (uv *Upvalue) Close()

func (*Upvalue) IsClosed

func (uv *Upvalue) IsClosed() bool

func (*Upvalue) SetValue

func (uv *Upvalue) SetValue(value LValue)

func (*Upvalue) Value

func (uv *Upvalue) Value() LValue


Path Synopsis
Lua pattern match functions for Go
Lua pattern match functions for Go

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