Draft: Resolve "Short circuiting and lazy evaluation"

Closes #49

src/virtmat/language/interpreter/instant_executor.py

@@ -39,10 +39,11 @@ comp_map = dict(zip(comp_operators, comp_functions))
 def log_eval(func):
     """a logger indicating when a value property is eventually evaluated"""
     logger = get_logger(__name__)
+
     def logged_value(obj):
-        ret = func(obj)
-        logger.debug(' evaluated %s: %s', repr(obj), ret)
-        return ret
+        ret_val = func(obj)
+        logger.debug(' evaluated %s: %s', repr(obj), ret_val)
+        return ret_val
     return logged_value