Add symbol to input check mapping

README.md

@@ -17,6 +17,7 @@ The VM defines the following opcode symbols:
 * `MAP <symbol>` - Expose a code symbol previously loaded by `LOAD` to the rendering client. Roughly corresponds to the `global` directive in Python.
 * `MOVE <symbol>` - Create a new execution frame, invalidating all previous `MAP` calls. More detailed: After a `MOVE` call, a `BACK` call will return to the same execution frame, with the same symbols available, but all `MAP` calls will have to be repeated.
 * `HALT` - Stop execution. The remaining bytecode (typically, the routing code for the node) is returned to the invoking function.
+* `INCMP <arg> <symbol>` - Compare registered input to `arg` and and move to `symbol` node on match. Any consecutive matches will be ignored until `HALT` is called.
 
 
 ### External code

go/engine/engine_test.go

@@ -85,7 +85,7 @@ func TestEngineInit(t *testing.T) {
 	if !bytes.Equal(b, []byte("hello world")) {
 		t.Fatalf("expected result 'hello world', got %v", b)
 	}
-	input := []byte("bar")
+	input := []byte("ooo")
 	err = en.Exec(input, ctx)
 	if err != nil {
 		t.Fatal(err)

go/vm/vm.go

@@ -169,6 +169,10 @@ func RunIncmp(instruction []byte, st *state.State, rs resource.Resource, ctx con
 	if err != nil {
 		return instruction, err
 	}
+	sym, tail, err := instructionSplit(tail)
+	if err != nil {
+		return instruction, err
+	}
 	v, err := st.GetFlag(state.FLAG_INMATCH)
 	if err != nil {
 		return tail, err
@@ -184,7 +188,7 @@ func RunIncmp(instruction []byte, st *state.State, rs resource.Resource, ctx con
 	if head == string(input) {
 		log.Printf("input match for '%s'", input)
 		_, err = st.SetFlag(state.FLAG_INMATCH)
-		st.Down(head)
+		st.Down(sym)
 	}
 	return tail, err
 }

go/vm/vm_test.go

@@ -232,10 +232,10 @@ func TestRunArg(t *testing.T) {
 	st := state.NewState(5)
 	rs := TestResource{}
 	
-	input := []byte("baz")
+	input := []byte("bar")
 	_ = st.SetInput(input)
 
-	bi := NewLine([]byte{}, INCMP, []string{"baz"}, nil, nil)
+	bi := NewLine([]byte{}, INCMP, []string{"bar", "baz"}, nil, nil)
 	b, err := Run(bi, &st, &rs, context.TODO())
 	if err != nil {
 		t.Error(err)	
@@ -254,10 +254,10 @@ func TestRunInputHandler(t *testing.T) {
 	st := state.NewState(5)
 	rs := TestResource{}
 
-	_ = st.SetInput([]byte("foo"))
+	_ = st.SetInput([]byte("baz"))
 
-	bi := NewLine([]byte{}, INCMP, []string{"bar"}, nil, nil)
+	bi := NewLine([]byte{}, INCMP, []string{"bar", "aiee"}, nil, nil)
-	bi = NewLine(bi, INCMP, []string{"foo"}, nil, nil)
+	bi = NewLine(bi, INCMP, []string{"baz", "foo"}, nil, nil)
 	bi = NewLine(bi, LOAD, []string{"one"}, nil, []uint8{0})
 	bi = NewLine(bi, LOAD, []string{"two"}, nil, []uint8{3})
 	bi = NewLine(bi, MAP, []string{"one"}, nil, nil)
@@ -282,7 +282,7 @@ func TestRunArgInvalid(t *testing.T) {
 
 	var err error
 
-	b := NewLine([]byte{}, INCMP, []string{"bar"}, nil, nil)
+	b := NewLine([]byte{}, INCMP, []string{"bar", "baz"}, nil, nil)
 	b = NewLine(b, CATCH, []string{"_catch"}, []byte{state.FLAG_INMATCH}, []uint8{1})
 
 	b, err = Run(b, &st, &rs, context.TODO())