// GoLuaFunc converts an arbitrary Go function into a Lua-compatible GoFunction.
// There are special optimized cases for functions that go from strings to strings,
// and doubles to doubles, but otherwise Go
// reflection is used to provide a generic wrapper function
func GoLuaFunc(L *lua.State, fun interface{}) lua.LuaGoFunction {
switch f := fun.(type) {
case func(*lua.State) int:
return f
case func(string) string:
return func(L *lua.State) int {
L.PushString(f(L.ToString(1)))
return 1
}
case func(float64) float64:
return func(L *lua.State) int {
L.PushNumber(f(L.ToNumber(1)))
return 1
}
default:
}
var funv reflect.Value
switch ff := fun.(type) {
case reflect.Value:
funv = ff
default:
funv = valueOf(fun)
}
funt := funv.Type()
targs, tout := functionArgRetTypes(funt)
return func(L *lua.State) int {
var lastT reflect.Type
isVariadic := funt.IsVariadic()
if isVariadic {
lastT = targs[len(targs)-1].Elem()
targs = targs[0 : len(targs)-1]
}
args := make([]reflect.Value, len(targs))
for i, t := range targs {
val := LuaToGo(L, t, i+1)
args[i] = valueOf(val)
}
if isVariadic {
n := L.GetTop()
for i := len(targs) + 1; i <= n; i++ {
val := valueOf(LuaToGo(L, lastT, i))
args = append(args, val)
}
}
resv := funv.Call(args)
for i, val := range resv {
GoToLua(L, tout[i], val)
}
return len(resv)
}
}