VariableContainerNamespace: allow getitem for parameters which cannot be python attributes

esrftaskgraph/esrftaskgraph/variable.py

@@ -334,8 +334,8 @@ class ReadOnlyVariableError(RuntimeError):
     pass
 
 
-class VariableContainerNamespace:
-    """Expose getting/setting variable values through attributes"""
+class ReadOnlyVariableContainerNamespace:
+    """Expose getting variable values through attributes"""
 
     def __init__(self, container):
         self._container = container
@@ -349,12 +349,16 @@ class VariableContainerNamespace:
         return cls._RESERVED_VARIABLE_NAMES
 
     def __setattr__(self, name, value):
-        if name in self._reserved_variable_names():
+        if name == "_container":
             super().__setattr__(name, value)
         else:
-            self._get_variable(name).value = value
+            self._get_variable(name)
+            raise ReadOnlyVariableError(name)
 
     def __getattr__(self, name):
+        return self[name]
+
+    def __getitem__(self, name):
         return self._get_variable(name).value
 
     def _get_variable(self, name):
@@ -364,9 +368,11 @@ class VariableContainerNamespace:
             raise MissingVariableError(name)
 
 
-class ReadOnlyVariableContainerNamespace(VariableContainerNamespace):
+class VariableContainerNamespace(ReadOnlyVariableContainerNamespace):
+    """Expose getting/setting variable values through attributes"""
+
     def __setattr__(self, name, value):
-        if name in self._reserved_variable_names():
-            super(VariableContainerNamespace, self).__setattr__(name, value)
+        if name == "_container":
+            super().__setattr__(name, value)
         else:
-            raise ReadOnlyVariableError(name)
+            self._get_variable(name).value = value