iterator interface chenged index and count members from int to tint 64

kern/iterator.go

@@ -30,8 +30,8 @@ type Iterator interface {
 	fmt.Stringer
 	Next() (item any, err error) // must return io.EOF after the last item
 	Current() (item any, err error)
-	Index() int
-	Count() int
+	Index() int64
+	Count() int64
 	HasOperation(name string) bool
 	CallOperation(name string, args map[string]any) (value any, err error)
 }

kern/number.go

@@ -75,3 +75,14 @@ func ToGoInt(value any, description string) (i int, err error) {
 	}
 	return
 }
+
+func ToGoInt64(value any, description string) (i int64, err error) {
+	if valueInt64, ok := value.(int64); ok {
+		i = valueInt64
+	} else if valueInt, ok := value.(int); ok {
+		i = int64(valueInt)
+	} else {
+		err = fmt.Errorf("%s expected integer, got %s (%v)", description, TypeName(value), value)
+	}
+	return
+}