Orest Kozyar wrote: > I'm trying to follow the example listed in the wiki at > http://www.sqlalchemy.org/trac/wiki/UsageRecipes/UniqueObject regarding the > use of a metaclass. > > What I don't understand is how the metaclass (EntitySingleton) has access to > the variable ctx which is instantinated outside the scope of the class > definition. Could anyone point me in the right direction please?
This is just basic name lookup rules. Names are looked up, in order, - in the scope of the current function - in the scope of any lexically enclosing functions - in the scope of the module containing the function (the 'global' scope) - in the built-in scope. ctx is defined at module level so the third step of the name lookup finds it. Not finding any great references but here are a few that might help: http://diveintopython.org/html_processing/locals_and_globals.html http://swaroopch.info/text/Special:Search?search=namespace&go=Go http://docs.python.org/ref/naming.html Kent _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
