Assert caching, lifting parser works within CEL

expr.go

@@ -202,6 +202,9 @@ func (a *aggregator) Add(ctx context.Context, eval Evaluable) (bool, error) {
 		return false, err
 	}
 
+	// NOTE: When modifying, ensure that Remove() is updated.  We should reconcile
+	// the core loops to use the same code.
+
 	aggregateable := true
 	for _, g := range parsed.RootGroups() {
 		ok, err := a.addGroup(ctx, g, parsed)
@@ -297,7 +300,16 @@ func (a *aggregator) addNode(ctx context.Context, n *Node, gid groupID, parsed *
 }
 
 func (a *aggregator) Remove(ctx context.Context, eval Evaluable) error {
-	// TODO
+	// parse the expression using our tree parser.
+	parsed, err := a.parser.Parse(ctx, eval)
+	if err != nil {
+		return err
+	}
+
+	for _, g := range parsed.RootGroups() {
+		_ = g
+	}
+
 	return fmt.Errorf("not implemented")
 }
 

lift.go

@@ -9,7 +9,7 @@ import (
 const (
 	// VarPrefix is the lifted variable name used when extracting idents from an
 	// expression.
-	VarPrefix = "vars."
+	VarPrefix = "vars"
 )
 
 var (
@@ -97,7 +97,7 @@ func (l *liftParser) addLiftedVar(val argMapValue) {
 	l.vars.vars[letter] = val
 	l.varCounter++
 
-	l.rewritten.WriteString(VarPrefix + letter)
+	l.rewritten.WriteString(VarPrefix + "." + letter)
 }
 
 func (l *liftParser) consumeString(quoteChar byte) argMapValue {

parser.go

@@ -540,7 +540,7 @@ func callToPredicate(item celast.Expr, negated bool, vars LiftedArgs) *Predicate
 		}
 
 		if aIsVar && vars != nil {
-			if val, ok := vars.Get(strings.TrimPrefix(identA, VarPrefix)); ok {
+			if val, ok := vars.Get(strings.TrimPrefix(identA, VarPrefix+".")); ok {
 				// Normalize.
 				literal = val
 				identA = identB
@@ -549,7 +549,7 @@ func callToPredicate(item celast.Expr, negated bool, vars LiftedArgs) *Predicate
 		}
 
 		if bIsVar && vars != nil {
-			if val, ok := vars.Get(strings.TrimPrefix(identB, VarPrefix)); ok {
+			if val, ok := vars.Get(strings.TrimPrefix(identB, VarPrefix+".")); ok {
 				// Normalize.
 				literal = val
 				identB = ""

parser_test.go

@@ -1079,6 +1079,51 @@ func TestParse_LiftedVars(t *testing.T) {
 	})
 }
 
+// TestParsedCELAST tests the CachingParser as a CEL parser, ensuring that complex expressions
+// can be evaluated using CEL when parsed.
+func TestParsedCELAST(t *testing.T) {
+	env := newEnv()
+
+	p := NewCachingParser(env, nil)
+
+	ast, iss, args := p.Parse("event.data.id == 'ok'")
+	require.Nil(t, iss)
+	require.EqualValues(t, map[string]any{"a": "ok"}, args.Map())
+
+	program, err := env.Program(
+		ast,
+		cel.EvalOptions(cel.OptExhaustiveEval, cel.OptTrackState, cel.OptPartialEval),
+	)
+	require.NoError(t, err)
+
+	t.Run("It returns true with a matching expression", func(t *testing.T) {
+		result, _, err := program.Eval(map[string]any{
+			"event": map[string]any{
+				"data": map[string]any{
+					"id": "ok",
+				},
+			},
+			"vars": args.Map(),
+		})
+		require.NoError(t, err)
+		require.EqualValues(t, result, true)
+	})
+
+	t.Run("It returns false with an invalid expression", func(t *testing.T) {
+		result, _, err := program.Eval(map[string]any{
+			"event": map[string]any{
+				"data": map[string]any{
+					"id": "no",
+				},
+			},
+			"vars": args.Map(),
+		})
+		require.NoError(t, err)
+		require.EqualValues(t, result, false)
+	})
+
+}
+
 func TestRootGroups(t *testing.T) {
 	r := require.New(t)
 	ctx := context.Background()