[E-Lang] E FAQ

[Marc Stiegler]

> (I should say that it might also make sense to ask, not only
> how early does a capabilities *need* to be revoked, but also
> how early can we revoke it, i.e., how soon can we say that
> the callee will never need it again.  Lest the distinction
> seem unimportant, my interest in the latter is on POLA grounds.)

To POLA-ize the duration of a capability, I would just like to remind
everyone that there's more than one way to decide revocation is appropriate.
A simple example is a once-only capability, for example the authority to
read the current price of a stock once, or the ability to write one object
only to the system clipboard. A more complex example might be a capability
that ORs together multiple revocation algorithms, for example, a write-once
capability to the clipboard that also has a timer that will destroy the
capability at the end of the count down, plus a revocation that is
automatically completed when the user initiates a copy operation from
another object.

--marcs