Zooko wrote:

...

Capabilities can loosely be thought of like bound methods. Security with capabilities is done based on possession; if you hold a reference to an object you can use that object.

No -- capabilities (as envisioned for Python) are references. Whether a reference to an object, to a bound method, or to a function doesn't matter.

Note that it isn't that capabilities are "like" references, it is that capabilities *are* references. Every reference is a capability. Every capability is a reference.

I should note that this is a new (and good) idea, not one that we've previously expressed. And, of course, they are references with restrictions, which will be spelt out in the PEP. Cheers, Ben. -- http://www.apache-ssl.org/ben.html http://www.thebunker.net/ "There is no limit to what a man can do or how far he can go if he doesn't mind who gets the credit." - Robert Woodruff