handle inner functions as lambdas

resolves #2287

Author: Fred Lefévère-Laoide

taipy/gui/_renderers/builder.py

@@ -171,7 +171,7 @@ def _get_variable_hash_names(
                 if _is_function(val) and not hash_name:
                     # if it's not a callable (and not a string), forget it
                     if _is_unnamed_function(val):
-                        # lambda or callable instance
+                        # lambda, inner function or callable instance
                         hash_name = _get_lambda_id(t.cast(LambdaType, val))
                         gui._bind_var_val(hash_name, val)  # type: ignore[arg-type]
                     else:

taipy/gui/builder/_element.py

@@ -108,7 +108,7 @@ def _parse_property(self, key: str, value: t.Any) -> t.Any:
             return value
         if isinstance(value, FunctionType):
             if key.startswith("on_") or self._is_callable(key):
-                return value if value.__name__.startswith("<") else value.__name__
+                return value if "<" in value.__qualname__ else value.__name__
             # Parse lambda function_is_callable
             if (lambda_call := self.__parse_lambda_property(key, value)) is not None:
                 return lambda_call

taipy/gui/utils/callable.py

@@ -27,4 +27,8 @@ def _function_name(s: t.Any) -> str:
 
 
 def _is_unnamed_function(s: t.Any):
-    return (hasattr(s, "__name__") and s.__name__ == "<lambda>") or (callable(s) and not hasattr(s, "__name__"))
+    return (
+        (hasattr(s, "__name__") and s.__name__ == "<lambda>")
+        or (callable(s) and not hasattr(s, "__name__"))
+        or (hasattr(s, "__qualname__") and "<locals>" in s.__qualname__)
+    )