On 7/30/09 2:07 PM, george hu wrote: > Hi Chris, > > I'm confused about the "callable" here. According to the official > python document - "Note that classes are callable (calling a class > returns a new instance); class instances are callable if they have a > call() method." When I look at the code of the SQLAlchemy Example, we > have this : > > class RootFactory(object): > __acl__ = [ (Allow, Everyone, 'view'), (Allow, 'editor', 'edit') ] > def __init__(self, environ): > self.__dict__.update(environ['bfg.routes.matchdict']) > > I don't think the RootFactory is callable in terms of class instance.
A callable is anything that can be called. A class is a callable. Instead of its __call__ being called, however, its __init__ is called. __init__ of a class returns a class instance. > And when I look at the source code of RoutesRootFactory, I think it is > the root factory in the description of "A root factory is a callable > that accepts an environ and returns a root". And the class above is > the "root" which returns by RoutesRootFactory In this case, the RootFactory's __init__ is called. A RootFactory is "returned". - C > > > On Wed, Jul 29, 2009 at 5:09 PM, Chris McDonough<chr...@plope.com> wrote: >> A root factory is a callable that accepts an environ and returns a root >> object. >> >> - C >> >> On 7/29/09 3:15 PM, george hu wrote: >>> It is said "root_factory must be a callable that accepts a ....". I >>> suspect it is not accurate. Instead, the root_factory here is >>> described in Glossary: " The “root factory” of an repoze.bfg >>> application is called on every request sent to the application." And >>> actually the user defined root_factory passed into the make_app >>> doesn't have to be callable. The callable object is RoutesRootFactory >>> which is called by "root=self.root_factory(environ)" in __call__ >>> function of Router class. >>> >>> The second point is, the user defined root_factory class must include >>> a constructor which accept a parameter of environ, because its >>> instance is created in RoutesRootFactory in a form of: return >>> factory(environ). >>> _______________________________________________ >>> Repoze-dev mailing list >>> Repoze-dev@lists.repoze.org >>> http://lists.repoze.org/listinfo/repoze-dev >>> >> > _______________________________________________ Repoze-dev mailing list Repoze-dev@lists.repoze.org http://lists.repoze.org/listinfo/repoze-dev
