[Python-Dev] Capabilities (we already got one)

Jeremy Hylton jeremy@zope.com
01 Apr 2003 12:10:16 -0500

On Tue, 2003-04-01 at 11:47, Zooko wrote:
> I think that in restricted-execution-mode (hereafter: "REM", as per Greg Ewing's 
> suggestion [1]), Python objects have encapsulation -- one can't access their 
> private data without their permission.
> Once this is done, Python references are capabilities.

REM does not provide object encapsulation, but it disables enough
introspection that it is possible to provide encapsulation.  The REM
implementation provides a Bastion function that creates private state by
storing the state in func_defaults, which is inaccessible in REM.