package main import ( "fmt" "io" "hilbish/util" rt "github.com/arnodel/golua/runtime" ) var sinkMetaKey = rt.StringValue("hshsink") // a sink is a structure that has input and/or output // it is like a lua file when used in popen, but specific to hilbish type sink struct{ writer io.Writer reader io.Reader ud *rt.UserData } func setupSinkType(rtm *rt.Runtime) { sinkMeta := rt.NewTable() sinkMethods := rt.NewTable() sinkFuncs := map[string]util.LuaExport{ "write": {luaSinkWrite, 2, false}, "writeln": {luaSinkWriteln, 2, false}, } util.SetExports(l, sinkMethods, sinkFuncs) sinkIndex := func(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) { arg := c.Arg(1) val := sinkMethods.Get(arg) return c.PushingNext1(t.Runtime, val), nil } sinkMeta.Set(rt.StringValue("__index"), rt.FunctionValue(rt.NewGoFunction(sinkIndex, "__index", 2, false))) l.SetRegistry(sinkMetaKey, rt.TableValue(sinkMeta)) } func luaSinkWrite(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) { if err := c.CheckNArgs(2); err != nil { return nil, err } s, err := sinkArg(c, 0) if err != nil { return nil, err } data, err := c.StringArg(1) if err != nil { return nil, err } s.writer.Write([]byte(data)) return c.Next(), nil } func luaSinkWriteln(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) { if err := c.CheckNArgs(2); err != nil { return nil, err } s, err := sinkArg(c, 0) if err != nil { return nil, err } data, err := c.StringArg(1) if err != nil { return nil, err } s.writer.Write([]byte(data + "\n")) return c.Next(), nil } func newSinkInput(r io.Reader) *sink { s := &sink{ reader: r, } s.ud = sinkUserData(s) return s } func newSinkOutput(w io.Writer) *sink { s := &sink{ writer: w, } s.ud = sinkUserData(s) return s } func sinkArg(c *rt.GoCont, arg int) (*sink, error) { s, ok := valueToSink(c.Arg(arg)) if !ok { return nil, fmt.Errorf("#%d must be a sink", arg + 1) } return s, nil } func valueToSink(val rt.Value) (*sink, bool) { u, ok := val.TryUserData() if !ok { return nil, false } s, ok := u.Value().(*sink) return s, ok } func sinkUserData(s *sink) *rt.UserData { sinkMeta := l.Registry(sinkMetaKey) return rt.NewUserData(s, sinkMeta.AsTable()) }