Make assembler handle non-DOWN menu choices

go/asm/asm.go

@@ -328,13 +328,20 @@ func(bt *Batcher) MenuExit(w io.Writer) (int, error) {
 func(bt *Batcher) MenuAdd(w io.Writer, code string, arg Arg) (int, error) {
 	bt.inMenu = true
 	var selector string
+	var sym string
 	if arg.Size != nil {
 		selector = strconv.FormatUint(uint64(*arg.Size), 10)
 	} else if arg.Selector != nil {
 		selector = *arg.Selector
 	}
-	log.Printf("menu processor add %v '%v' '%v' '%v'", code, *arg.Sym, selector, *arg.Desc)
-	err := bt.menuProcessor.Add(code, *arg.Sym, selector, *arg.Desc)
+
+	if selector == "" {
+		selector = *arg.Sym
+	} else if arg.Sym != nil {
+		sym = *arg.Sym
+	}
+	log.Printf("menu processor add %v '%v' '%v' '%v'", code, selector, *arg.Desc, sym)
+	err := bt.menuProcessor.Add(code, selector, *arg.Desc, sym)
 	return 0, err
 }
 

go/asm/asm_test.go

@@ -94,7 +94,7 @@ func TestParseDouble(t *testing.T) {
 
 func TestParseMenu(t *testing.T) {
 	s := `DOWN foobar 00 "inky pinky"
-UP bazbar s1 "tinkywinky"
+UP s1 "tinkywinky"
 `
 	r := bytes.NewBuffer(nil)
 	n, err := Parse(s, r)

go/asm/menu.go

@@ -48,6 +48,9 @@ func(mp *MenuProcessor) Add(bop string, choice string, display string, target st
 	if bopCode == 0 {
 		return fmt.Errorf("unknown menu instruction: %v", bop)
 	}
+	if len(target) > 0 && bopCode != MENU_DOWN {
+		return fmt.Errorf("target is only valid for DOWN")
+	}
 	m := menuItem{
 		code: bopCode,
 		choice: choice,

go/asm/menu_test.go

@@ -13,15 +13,15 @@ func TestMenuInterpreter(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	err = m.Add("NEXT", "1", "pinky", "bar")
+	err = m.Add("NEXT", "1", "pinky", "")
 	if err != nil {
 		t.Fatal(err)
 	}
-	err = m.Add("PREVIOUS", "2", "blinky clyde", "baz")
+	err = m.Add("PREVIOUS", "2", "blinky clyde", "")
 	if err != nil {
 		t.Fatal(err)
 	}
-	err = m.Add("UP", "99", "tinky-winky", "xyzzy")
+	err = m.Add("UP", "99", "tinky-winky", "")
 	if err != nil {
 		t.Fatal(err)
 	}

go/testdata/foo.fst

@@ -6,3 +6,4 @@ INCMP 1 _
 INCMP 2 baz
 CATCH _catch 1 1
 DOWN foofoo 1 "go to foo"
+UP 2 "up go go go"