diff options
Diffstat (limited to 'lua.go')
| -rw-r--r-- | lua.go | 72 |
1 files changed, 72 insertions, 0 deletions
@@ -22,7 +22,9 @@ import "C" import ( "errors" "fmt" + "reflect" "runtime/cgo" + "slices" "unsafe" ) @@ -231,6 +233,76 @@ func (l *Lua) LoadString(code string) error { return nil } +// Scan scans values from the Lua stack into vars according to their types. +func (l *Lua) Scan(vars ...any) error { + slices.Reverse(vars) + for i, v := range vars { + t := reflect.TypeOf(v) + // unwrap pointers + for t.Kind() == reflect.Ptr { + t = t.Elem() + } + tk := t.Kind() + if t.Name() == "LuaRef" { + if l.IsFunction(-1) == false { + return fmt.Errorf( + "passed arg #%d must be function", + len(vars)-i, + ) + } + *v.(*LuaRef) = l.PopToRef() + } else if tk == reflect.String { + if l.IsString(-1) == false { + return fmt.Errorf( + "passed arg #%d must be string", + len(vars)-i, + ) + } + *v.(*string) = l.ToString(-1) + l.Pop(1) + } else if tk == reflect.Int { + if l.IsNumber(-1) == false { + return fmt.Errorf( + "passed arg #%d must be number", + len(vars)-i, + ) + } + *v.(*int) = l.ToInt(-1) + l.Pop(1) + } else if tk == reflect.Map && t.Key().Kind() == reflect.String { + // TODO: should be possible to use maps with any types + // of value, not only strings. + vm, _ := v.(*map[string]string) + l.PushNil() + for l.Next() { + if !l.IsString(-1) { + return fmt.Errorf( + "map arg #%d must only have string values", + len(vars)-i, + ) + } + if !l.IsString(-2) { + return fmt.Errorf( + "map arg #%d must only have string keys", + len(vars)-i, + ) + } + iv := l.ToString(-1) + l.Pop(1) + // We must not pop the item key from the stack + // because otherwise C.lua_next won't work + // properly. + k := l.ToString(-1) + (*vm)[k] = iv + } + l.Pop(1) + } else { + return fmt.Errorf("unknown var type: %s", t) + } + } + return nil +} + // RestoreStackFunc remembers the Lua stack size and then restores it when a // returned function is called. It's a helper function to avoid stack leakage. func (l *Lua) RestoreStackFunc() func () { |