diff --git a/src/dynamicprompts/parser/parse.py b/src/dynamicprompts/parser/parse.py
index 56cacfe..51bce52 100644
--- a/src/dynamicprompts/parser/parse.py
+++ b/src/dynamicprompts/parser/parse.py
@@ -440,9 +440,7 @@ def create_parser(
     # stripped with variable access. This restores them so that the
     # variable can be properly recognized at a later stage
     variable_ref.set_parse_action(
-        lambda s, l, t: parser_config.variable_start
-        + "".join(t)
-        + parser_config.variable_end,
+        lambda string, location, token: f"{parser_config.variable_start}{''.join(token)}{parser_config.variable_end}",
     )
 
     variable_assignment = _configure_variable_assignment(
diff --git a/src/dynamicprompts/samplers/utils.py b/src/dynamicprompts/samplers/utils.py
index 34b4d0e..7171dbf 100644
--- a/src/dynamicprompts/samplers/utils.py
+++ b/src/dynamicprompts/samplers/utils.py
@@ -89,8 +89,8 @@ def replace_wildcard_variables(
     try:
         wildcard_result = wildcard.parse_string(command.wildcard)
         return command.with_content("".join(wildcard_result))
-    except Exception as ex:
-        logger.warning("Unable to parse wildcard path %s", command.wildcard)
+    except Exception:
+        logger.warning("Unable to parse wildcard %r", command.wildcard, exc_info=True)
         return command
 
 
@@ -114,4 +114,6 @@ def _replace_variable(string, location, token, *, variables: dict):
 
         if isinstance(variable, LiteralCommand):
             variable = variable.literal
+        if not isinstance(variable, str):
+            raise NotImplementedError("evaluating complex commands within wildcards is not supported right now")    
     return variable or default or var_name