Re: active values

[kanderso%dino.bbn.com@RELAY.CS.NET]

I can't answer for variables in general, but you can have active slot
values in CLOS by defining a metaclass.  One way that we have done it
is to define an active-value  object that has a true value and
actions to be performed on get and put.  When a slot value is
accessed, the metaclass would check if the slot contained an
active-value and act accordingly.  Thus the cost is a type check on
every slot access.

k