fix unreliable Stack.Fold method behavior

cfg.go

@@ -85,6 +85,11 @@ func (r stack) stackType() stackType {
 	return sc.stackType()
 }
 
+func (r stack) stackKind() string {
+	sc, _ := r.config()
+	return sc.kind()
+}
+
 func (r nodeConfig) isError() bool {
 	return r.err != nil
 }
@@ -151,11 +156,7 @@ func (r *nodeConfig) kind() (kind string) {
 
 	switch r.typ {
 	case and, or, not, list, cond:
-		kind = r.typ.String()
-	}
-
-	if r.positive(cfold) {
-		kind = lc(kind)
+		kind = foldValue(r.positive(cfold), r.typ.String())
 	}
 
 	return

stack.go

@@ -1929,7 +1929,7 @@ with an implicit null uint8 value (0x0).
 */
 func (r stack) typ() (kind string, typ stackType) {
 	typ = r.stackType()
-	kind = typ.String()
+	kind = r.kind()
 	if sym := r.getSymbol(); len(sym) > 0 {
 		kind = sym
 	} else if !(typ == list || typ == basic) {

stack_test.go

@@ -38,7 +38,7 @@ func TestStack_And001(t *testing.T) {
 		`testing3`,
 	)
 
-	want := `( testing1 AND testing2 AND testing3 )`
+	want := `( testing1 and testing2 and testing3 )`
 	if got.String() != want {
 		t.Errorf("%s failed: want '%s', got '%s'", t.Name(), want, got)
 	}
@@ -53,19 +53,19 @@ func TestStack_Insert(t *testing.T) {
 
 	got.Insert(`testing0`, 0)
 
-	want := `( testing0 AND testing1 AND testing2 AND testing3 )`
+	want := `( testing0 and testing1 and testing2 and testing3 )`
 	if got.String() != want {
 		t.Errorf("%s.1 failed: want '%s', got '%s'", t.Name(), want, got)
 	}
 
 	got.Insert(`testing2.5`, 3)
-	want = `( testing0 AND testing1 AND testing2 AND testing2.5 AND testing3 )`
+	want = `( testing0 and testing1 and testing2 and testing2.5 and testing3 )`
 	if got.String() != want {
 		t.Errorf("%s.2 failed: want '%s', got '%s'", t.Name(), want, got)
 	}
 
 	got.Insert(`testing4`, 15)
-	want = `( testing0 AND testing1 AND testing2 AND testing2.5 AND testing3 AND testing4 )`
+	want = `( testing0 and testing1 and testing2 and testing2.5 and testing3 and testing4 )`
 	if got.String() != want {
 		t.Errorf("%s.3 failed: want '%s', got '%s'", t.Name(), want, got)
 	}