[cap-talk] Deep attenuation, typed operations

[Jed Donnelley]

----- Original Message -----
From: Charles Landau <clandau at macslab.com>
Date: Friday, August 17, 2007 9:07 am
Subject: Re: [cap-talk] Deep attenuation, typed operations
To: jed at nersc.gov, "General discussions concerning capability systems." <cap-talk at mail.eros-os.org>

> At 8:24 AM -0700 8/15/07, Jed Donnelley wrote:
> >If I don't know about object types and their operations that may
> >be present deep in the structure, then the default mechanism
> >'fails' soft - that it it denies any unknown operations.
> 
> Yes, but it fails.
> 
> >However, with the extension that I mentioned in my last
> >message (wild cards, albut. etc.) one can certainly include
> >[read,*] to get the same effect.
> 
> I think that is the effect you always want, and allowing specifying 
> types (other than *) only invites failure.

We could certainly start with that approach in an initial "CapDoc"
implementation.  One thing I like about that approach is that
it puts some amount of pressure on those implementing
objects to give comparable/compatible operations the same
name.  If that 'pressure' is adequate then perhaps nothing
like the more general typed mechanism for deep attenuation
will be needed.
...

--JED  http://www.nersc.gov/~jed/