diff --git a/Makefile b/Makefile
index ad93bda..4b3d476 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-examples: profile session helloworld
+examples: profile session helloworld validate
 
 .PHONY: examples
 
@@ -10,3 +10,6 @@ session:
 
 helloworld:
 	bash examples/compile.bash examples/helloworld
+
+validate:
+	bash examples/compile.bash examples/validate
diff --git a/examples/validate/end b/examples/validate/end
new file mode 100644
index 0000000..5806299
--- /dev/null
+++ b/examples/validate/end
@@ -0,0 +1,2 @@
+You made it.
+Any input to go again.
diff --git a/examples/validate/end.vis b/examples/validate/end.vis
new file mode 100644
index 0000000..5a059f3
--- /dev/null
+++ b/examples/validate/end.vis
@@ -0,0 +1,3 @@
+HALT
+LOAD again 0
+INCMP * _
diff --git a/examples/validate/main.go b/examples/validate/main.go
new file mode 100644
index 0000000..7add04e
--- /dev/null
+++ b/examples/validate/main.go
@@ -0,0 +1,84 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"os"
+	"path"
+
+	testdataloader "github.com/peteole/testdata-loader"
+
+	"git.defalsify.org/vise/cache"
+	"git.defalsify.org/vise/engine"
+	"git.defalsify.org/vise/resource"
+	"git.defalsify.org/vise/state"
+)
+
+var (
+	baseDir = testdataloader.GetBasePath()
+	scriptDir = path.Join(baseDir, "examples", "validate")
+	emptyResult = resource.Result{}
+)
+
+const (
+	USERFLAG_HAVESOMETHING = state.FLAG_USERSTART
+)
+
+type verifyResource struct {
+	*resource.FsResource
+	st *state.State
+}
+
+func(vr *verifyResource) verify(sym string, input []byte, ctx context.Context) (resource.Result, error) {
+	var err error
+	if string(input) == "something" {
+		_, err = vr.st.SetFlag(USERFLAG_HAVESOMETHING)
+	}
+	return resource.Result{
+		Content: "",
+	}, err
+}
+
+func(vr *verifyResource) again(sym string, input []byte, ctx context.Context) (resource.Result, error) {
+	var err error
+	_, err = vr.st.ResetFlag(USERFLAG_HAVESOMETHING)
+	return resource.Result{}, err
+}
+
+func main() {
+	var root string
+	var size uint
+	var sessionId string
+	flag.UintVar(&size, "s", 0, "max size of output")
+	flag.StringVar(&root, "root", "root", "entry point symbol")
+	flag.StringVar(&sessionId, "session-id", "default", "session id")
+	flag.Parse()
+	fmt.Fprintf(os.Stderr, "starting session at symbol '%s' using resource dir: %s\n", root, scriptDir)
+
+	st := state.NewState(1)
+	rsf := resource.NewFsResource(scriptDir)
+	rs := verifyResource{&rsf, &st}
+	rs.AddLocalFunc("verifyinput", rs.verify)
+	rs.AddLocalFunc("again", rs.again)
+	ca := cache.NewCache()
+	cfg := engine.Config{
+		Root: "root",
+		SessionId: sessionId,
+		OutputSize: uint32(size),
+	}
+	ctx := context.Background()
+	ctx = context.WithValue(ctx, "SessionId", sessionId)
+	en := engine.NewEngine(cfg, &st, rs, ca, ctx)
+	var err error
+	_, err = en.Init(ctx)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "engine init fail: %v\n", err)
+		os.Exit(1)
+	}
+	err = engine.Loop(&en, os.Stdin, os.Stdout, ctx)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "loop exited with error: %v\n", err)
+		os.Exit(1)
+	}
+}
diff --git a/examples/validate/root b/examples/validate/root
new file mode 100644
index 0000000..6021dd8
--- /dev/null
+++ b/examples/validate/root
@@ -0,0 +1 @@
+Please write "something"
diff --git a/examples/validate/root.vis b/examples/validate/root.vis
new file mode 100644
index 0000000..3125a8f
--- /dev/null
+++ b/examples/validate/root.vis
@@ -0,0 +1,6 @@
+LOAD verifyinput 0
+MAP verifyinput
+HALT
+RELOAD verifyinput
+CATCH . 8 1
+MOVE end
diff --git a/vm/runner.go b/vm/runner.go
index cffdd7d..43240fa 100644
--- a/vm/runner.go
+++ b/vm/runner.go
@@ -192,23 +192,29 @@ func(vm *Vm) RunCatch(b []byte, ctx context.Context) ([]byte, error) {
 	}
 	r, err := vm.st.MatchFlag(sig, mode)
 	if err != nil {
-		_, err = vm.st.SetFlag(state.FLAG_TERMINATE)
-		if err != nil {
-			panic(err)
+		var perr error
+		_, perr = vm.st.SetFlag(state.FLAG_TERMINATE)
+		if perr != nil {
+			panic(perr)
 		}
 		log.Printf("terminate set")
 		return b, err
 	}
 	if r {
-		log.Printf("catch at flag %v, moving to %v", sig, sym) //bitField, d)
+		//b = append(bh, b...)
+		//vm.st.Down(sym)
+		//vm.ca.Push()
+		actualSym, _, err := applyTarget([]byte(sym), vm.st, vm.ca, ctx)
+		if err != nil {
+			return b, err
+		}
+		log.Printf("catch at flag %v, moving to '%v' ('%v')", sig, sym, actualSym)
+		sym = actualSym
 		bh, err := vm.rs.GetCode(sym)
 		if err != nil {
 			return b, err
 		}
-		//b = append(bh, b...)
 		b = bh
-		vm.st.Down(sym)
-		vm.ca.Push()
 	}
 	return b, nil
 }