--- a/svghmi/widget_assign.ysl2	Thu Mar 28 12:07:24 2024 +0100
+++ b/svghmi/widget_assign.ysl2	Wed Apr 03 14:17:50 2024 +0200
@@ -71,7 +71,7 @@
         const "name","substring-before(@value,'=')";
         const "value","substring-after(@value,'=')";
         const "index" foreach "$paths" if "@assign = $name" value "position()-1";
-        const "isVarName", "regexp:test($value,'^[a-zA-Z_][a-zA-Z0-9_]+$')";
+        const "isVarName", "regexp:test($value,'^[a-zA-Z_][a-zA-Z0-9_]*$')";
         choose {
             when "$isVarName"{
     |         const «$value» = this.assignments["«$value»"];