WIP

jp/get.go

@@ -826,7 +826,8 @@ func (x Expr) Get(data any) (results []any) {
 			}
 		case *Filter:
 			before := len(stack)
-			stack, _ = tf.EvalWithRoot(stack, prev, data).([]any)
+			ns, _ := tf.evalWithRoot(stack, prev, data)
+			stack, _ = ns.([]any)
 			if int(fi) == len(x)-1 { // last one
 				for i := len(stack) - 1; before <= i; i-- {
 					results = append(results, stack[i])
@@ -1616,7 +1617,8 @@ func (x Expr) FirstFound(data any) (any, bool) {
 			}
 		case *Filter:
 			before := len(stack)
-			stack, _ = tf.EvalWithRoot(stack, prev, data).([]any)
+			ns, _ := tf.evalWithRoot(stack, prev, data)
+			stack, _ = ns.([]any)
 			if int(fi) == len(x)-1 { // last one
 				if before < len(stack) {
 					result := stack[len(stack)-1]

jp/has.go

@@ -755,7 +755,8 @@ func (x Expr) Has(data any) bool {
 			}
 		case *Filter:
 			before := len(stack)
-			stack, _ = tf.EvalWithRoot(stack, prev, data).([]any)
+			ns, _ := tf.evalWithRoot(stack, prev, data)
+			stack, _ = ns.([]any)
 			if int(fi) == len(x)-1 { // last one
 				if before < len(stack) {
 					stack = stack[:before]

jp/modify.go

@@ -795,7 +795,8 @@ done:
 					}
 				}
 			} else {
-				stack, _ = tf.EvalWithRoot(stack, prev, data).([]any)
+				ns, _ := tf.evalWithRoot(stack, prev, data)
+				stack, _ = ns.([]any)
 			}
 		case Descent:
 			di, _ := stack[len(stack)-1].(fragIndex)

jp/node.go

@@ -322,7 +322,8 @@ func (x Expr) GetNodes(n gen.Node) (results []gen.Node) {
 			}
 		case *Filter:
 			before := len(stack)
-			stack, _ = tf.EvalWithRoot(stack, prev, n).([]gen.Node)
+			ns, _ := tf.evalWithRoot(stack, prev, n)
+			stack, _ = ns.([]gen.Node)
 			if int(fi) == len(x)-1 { // last one
 				for i := before; i < len(stack); i++ {
 					results = append(results, stack[i])
@@ -589,7 +590,8 @@ func (x Expr) FirstNode(n gen.Node) (result gen.Node) {
 			}
 		case *Filter:
 			before := len(stack)
-			stack, _ = tf.EvalWithRoot(stack, prev, n).([]gen.Node)
+			ns, _ := tf.evalWithRoot(stack, prev, n)
+			stack, _ = ns.([]gen.Node)
 			if int(fi) == len(x)-1 { // last one
 				if before < len(stack) {
 					result := stack[before]

jp/script.go

@@ -160,20 +160,23 @@ func (s *Script) String() string {
 func (s *Script) Match(data any) bool {
 	stack := []any{}
 	if node, ok := data.(gen.Node); ok {
-		stack, _ = s.EvalWithRoot(stack, gen.Array{node}, data).([]any)
+		ns, _ := s.evalWithRoot(stack, gen.Array{node}, data)
+		stack, _ = ns.([]any)
 	} else {
-		stack, _ = s.EvalWithRoot(stack, []any{data}, data).([]any)
+		ns, _ := s.evalWithRoot(stack, []any{data}, data)
+		stack, _ = ns.([]any)
 	}
 	return 0 < len(stack)
 }
 
 // Eval is primarily used by the Expr parser but is public for testing.
 func (s *Script) Eval(stack any, data any) any {
-	return s.EvalWithRoot(stack, data, nil)
+	ns, _ := s.evalWithRoot(stack, data, nil)
+	return ns
 }
 
-// EvalWithRoot is primarily used by the Expr parser but is public for testing.
-func (s *Script) EvalWithRoot(stack any, data, root any) any {
+// evalWithRoot is primarily used by the Expr parser but is public for testing.
+func (s *Script) evalWithRoot(stack any, data, root any) (any, Expr) {
 	// Checking the type each iteration adds 2.5% but allows code not to be
 	// duplicated and not to call a separate function. Using just one more
 	// function call for each iteration adds 6.5%.
@@ -210,7 +213,7 @@ func (s *Script) EvalWithRoot(stack any, data, root any) any {
 	default:
 		rv := reflect.ValueOf(td)
 		if rv.Kind() != reflect.Slice && rv.Kind() != reflect.Array {
-			return stack
+			return stack, nil
 		}
 		dlen = rv.Len()
 		da := make([]any, 0, dlen)
@@ -646,7 +649,7 @@ func (s *Script) EvalWithRoot(stack any, data, root any) any {
 	for i := range sstack {
 		sstack[i] = nil
 	}
-	return stack
+	return stack, nil
 }
 
 // Inspect the script.

jp/set.go

@@ -1145,7 +1145,8 @@ func (x Expr) set(data, value any, fun string, one bool) error {
 				}
 			}
 		case *Filter:
-			stack, _ = tf.EvalWithRoot(stack, prev, data).([]any)
+			ns, _ := tf.evalWithRoot(stack, prev, data)
+			stack, _ = ns.([]any)
 		case Root:
 			stack = append(stack, data)
 		case At, Bracket: