func main() {
var L *lua.State
L = lua.NewState()
defer L.Close()
L.OpenLibs()
// just to show we can catch the panic
defer func() {
fmt.Println("done")
if x := recover(); x != nil {
fmt.Printf("run time panic: %v", x)
}
}()
// we can still catch the panic without this,
// but it allows us to do some custom recovery
currentPanicf := L.AtPanic(nil)
currentPanicf = L.AtPanic(currentPanicf)
newPanic := func(L1 *lua.State) int {
fmt.Println("I AM PANICKING!!!")
return currentPanicf(L1)
}
L.AtPanic(newPanic)
//force a panic
L.PushNil()
L.Call(0, 0)
}
// Push a Go value 'val' of type 't' on the Lua stack.
func GoToLua(L *lua.State, t reflect.Type, val reflect.Value) {
if t == nil {
t = val.Type()
}
if t.Kind() == reflect.Ptr {
t = t.Elem()
}
switch t.Kind() {
case reflect.Float64:
case reflect.Float32:
{
L.PushNumber(val.Float())
}
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32:
{
L.PushNumber(float64(val.Int()))
}
case reflect.Uint, reflect.Uint8:
{
L.PushNumber(float64(val.Uint()))
}
case reflect.String:
{
L.PushString(val.String())
}
case reflect.Bool:
{
L.PushBoolean(val.Bool())
}
case reflect.Slice:
{
makeValueProxy(L, val, SLICE_META)
}
case reflect.Map:
{
makeValueProxy(L, val, MAP_META)
}
case reflect.Struct:
{
makeValueProxy(L, val, STRUCT_META)
}
default:
{
// fmt.Println("unhandled go type",t,t.Kind())
if val.IsNil() {
L.PushNil()
} else {
makeValueProxy(L, val, INTERFACE_META)
}
}
}
}
// copy a Go slice to a Lua table
func CopySliceToTable(L *lua.State, vslice reflect.Value) int {
if vslice.IsValid() && vslice.Type().Kind() == reflect.Slice {
n := vslice.Len()
L.CreateTable(n, 0)
for i := 0; i < n; i++ {
L.PushInteger(i + 1)
GoToLua(L, nil, vslice.Index(i))
L.SetTable(-3)
}
return 1
} else {
L.PushNil()
L.PushString("not a slice!")
}
return 2
}
// copy a Go map to a Lua table
func CopyMapToTable(L *lua.State, vmap reflect.Value) int {
if vmap.IsValid() && vmap.Type().Kind() == reflect.Map {
n := vmap.Len()
L.CreateTable(0, n)
for _, key := range vmap.MapKeys() {
val := vmap.MapIndex(key)
GoToLua(L, nil, key)
GoToLua(L, nil, val)
L.SetTable(-3)
}
return 1
} else {
L.PushNil()
L.PushString("not a map!")
}
return 2
}
func copyMapToTable(L *lua.State) int {
vmap := valueOf(unwrapProxy(L, 1))
if vmap.IsValid() && vmap.Type().Kind() == reflect.Map {
n := vmap.Len()
L.CreateTable(0, n)
for _, key := range vmap.MapKeys() {
GoToLua(L, nil, key)
GoToLua(L, nil, vmap.MapIndex(key))
L.SetTable(-3)
}
return 1
} else {
L.PushNil()
L.PushString("not a map!")
}
return 2
}
// return the Lua table at 'idx' as a copied Go map. If 't' is nil then the map
// type is map[string]interface{}
func CopyTableToMap(L *lua.State, t reflect.Type, idx int) interface{} {
if t == nil {
t = reflect.TypeOf(tmap)
}
te, tk := t.Elem(), t.Key()
m := reflect.MakeMap(t)
L.PushNil()
if idx < 0 {
idx--
}
for L.Next(idx) != 0 {
// key at -2, value at -1
key := valueOf(LuaToGo(L, tk, -2))
val := valueOf(LuaToGo(L, te, -1))
m.SetMapIndex(key, val)
L.Pop(1)
}
return m.Interface()
}
func CopyTableToStruct(L *lua.State, t reflect.Type, idx int) interface{} {
if t.Kind() == reflect.Ptr {
t = t.Elem()
}
s := reflect.New(t) // T -> *T
ref := s.Elem()
L.PushNil()
if idx < 0 {
idx--
}
for L.Next(idx) != 0 {
key := L.ToString(-2)
f := ref.FieldByName(key)
if f.IsValid() {
val := valueOf(LuaToGo(L, f.Type(), -1))
f.Set(val)
}
L.Pop(1)
}
return s.Interface()
}
// Push a Go value 'val' of type 't' on the Lua stack.
// If we haven't been given a concrete type, use the type of the value
// and unbox any interfaces.
func GoToLua(L *lua.State, t reflect.Type, val reflect.Value) {
proxify := true
if t == nil {
t = val.Type()
if t.Kind() == reflect.Interface { // unbox interfaces!
val = valueOf(val.Interface())
t = val.Type()
}
proxify = false
}
if t.Kind() == reflect.Ptr {
t = t.Elem()
}
switch t.Kind() {
case reflect.Float64:
case reflect.Float32:
{
L.PushNumber(val.Float())
}
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32:
{
L.PushNumber(float64(val.Int()))
}
case reflect.Uint, reflect.Uint8:
{
L.PushNumber(float64(val.Uint()))
}
case reflect.String:
{
L.PushString(val.String())
}
case reflect.Bool:
{
L.PushBoolean(val.Bool())
}
case reflect.Slice:
{
if proxify {
makeValueProxy(L, val, SLICE_META)
} else {
CopySliceToTable(L, val)
}
}
case reflect.Map:
{
if proxify {
makeValueProxy(L, val, MAP_META)
} else {
CopyMapToTable(L, val)
}
}
case reflect.Struct:
{
makeValueProxy(L, val, STRUCT_META)
}
default:
{
if val.IsNil() {
L.PushNil()
} else {
makeValueProxy(L, val, INTERFACE_META)
}
}
}
}