tagging was bad

internal/sim/player.go

@@ -9,7 +9,6 @@ import (
 // player represents a player character in the simulation
 type player struct {
 	*blammo.Log
-	sessionID int
 	entityID int
 }
 

internal/sim/world.go

@@ -62,7 +62,6 @@ func (w *World) SpawnPlayer(id int) int {
 	t := &r.tiles[0]
 	p := player{
 		Log:      w.Child("players").Child(strconv.Itoa(id)),
-		sessionID: id,
 		entityID: w.lastEntityID,
 	}
 	t.addEntity(&p)

internal/wire/error.go

@@ -9,9 +9,13 @@ type Error struct {
 }
 
 func (e Error) Error() string  { return e.val.Error() }
-func (e Error) NetTag() Tag   { return T_Error }
+func (e Error) NetTag() string { return "error" }
 func (e Error) Unwrap() error  { return e.val }
 
 func Errorf(t string, args ...interface{}) Error {
 	return Error{val: fmt.Errorf(t, args...)}
 }
+
+func init() {
+	Register(func() Value { return new(Error) })
+}

internal/wire/ok.go

@@ -1,4 +1,9 @@
 package wire
 
-type OK struct {}
-func (OK) NetTag() Tag { return T_OK }
+type OK struct{}
+
+func (OK) NetTag() string { return "ok" }
+
+func init() {
+	Register(func() Value { return new(OK) })
+}

internal/wire/request.go

@@ -2,7 +2,7 @@ package wire
 
 type Request struct {
 	Seq  int         `json:"seq"`
-	Type Tag         `json:"type"`
+	Type string      `json:"type"`
 	Body interface{} `json:"body"`
 }
 

internal/wire/response.go

@@ -2,7 +2,7 @@ package wire
 
 type Response struct {
 	Re   int         `json:"re,omitempty"`
-	Type Tag         `json:"type"`
+	Type string      `json:"type"`
 	Body interface{} `json:"body"`
 }
 

internal/wire/self.go

@@ -6,4 +6,4 @@ type Self_Move struct {
 	Y     int  `json:"y"`
 }
 
-func (Self_Move) NetTag() Tag { return T_Client_Move }
+func (Self_Move) NetTag() string { return "self/move" }

internal/wire/tag.go

@@ -1,51 +0,0 @@
-package wire
-
-import (
-	"encoding/json"
-	"fmt"
-)
-
-type Tag uint
-
-const (
-	T_None Tag = iota
-	T_Error
-	T_OK
-	T_Client_Move
-)
-
-func (t Tag) String() string {
-	switch t {
-	case T_Error:
-		return "error"
-	case T_OK:
-		return "ok"
-	case T_Client_Move:
-		return "self/move"
-	default:
-		panic("unknown type tag")
-	}
-}
-
-func (t *Tag) UnmarshalJSON(b []byte) error {
-	var name string
-	if err := json.Unmarshal(b, &name); err != nil {
-		return err
-	}
-
-	switch name {
-	case "error":
-		*t = T_Error
-		return nil
-	case "ok":
-		*t = T_OK
-		return nil
-	case "self/move":
-		*t = T_Client_Move
-		return nil
-	default:
-		return fmt.Errorf("unknown type tag: %q", name)
-	}
-}
-
-func (t Tag) MarshalJSON() ([]byte, error) { return json.Marshal(t.String()) }

internal/wire/value.go

@@ -1,3 +1,24 @@
 package wire
 
-type Value interface{ NetTag() Tag }
+type Value interface {
+	NetTag() string
+}
+
+var registry = make(map[string]func() Value)
+
+func Register(f func() Value) {
+	v := f()
+	t := v.NetTag()
+	if _, exists := registry[t]; exists {
+		panic("cannot register type: a type already exists with tag " + t)
+	}
+	registry[t] = f
+}
+
+func New(name string) Value {
+	f, ok := registry[name]
+	if !ok {
+		return nil
+	}
+	return f()
+}