[Exp PyROOT] Implemented the possibility to call a namespace inside...

[Exp PyROOT] Implemented the possibility to call a namespace inside cppyy.gbl.ROOT by typing simply ROOT.namespace instead of ROOT.ROOT.namespace

bindings/pyroot_experimental/PyROOT/python/ROOT/_facade.py

@@ -44,6 +44,14 @@ class ROOTFacade(types.ModuleType):
         self.__class__.__getattr__ = self._getattr
         self.__class__.__setattr__ = self._setattr
 
+    def _fallback_getattr(self, name):
+        # Try first in the global namespace, then in the ROOT namespace
+        # This allows to lookup e.g. ROOT.ROOT.Math as ROOT.Math
+        try:
+            return getattr(gbl_namespace, name)
+        except AttributeError:
+            return getattr(self.__dict__['ROOT_ns'], name)
+
     def _finalSetup(self):
         # Setup interactive usage from Python
         self.__dict__['app'] = PyROOTApplication(self.PyConfig)
@@ -51,7 +59,8 @@ class ROOTFacade(types.ModuleType):
             self.app.init_graphics()
 
         # Redirect lookups to cppyy's global namespace
-        self.__class__.__getattr__ = lambda self, name: getattr(gbl_namespace, name)
+        self.__dict__['ROOT_ns'] = gbl_namespace.ROOT
+        self.__class__.__getattr__ = self._fallback_getattr
         self.__class__.__setattr__ = lambda self, name, val: setattr(gbl_namespace, name, val)
 
     def _getattr(self, name):