Sigh...
Ok, I'll make sure the same facility is available in the new code base.
How painful would it be if I changed the interface to this
functionality? I'd like to make derived indices part of the class
definition rather than a dynamic facility. It simplifies schema
evolution to have all the specs for a given class in one place so
there is one master 'version' of the object to work from.
I'm thinking something like:
(defpclass foo ()
((slot1 :accessor slot1 ...)
(slot2 :accessor slot2 ...)
(slot3 :accessor slot3 ...)
(derived :reader foo-value :derived-fn my-fn :index t :slot-deps
(slot1 slot3))))
This means you now have an indexed slot who's index value is
determined by the value returned by my-fn whenever slot1 or slot3 are
written. No slot storage is actually used. If you use the reader, it
just calls my-fn on the object to give you a value.
You can also register a lambda expression instead of a function symbol.
Would this work for your system?
Ian
On Mar 21, 2008, at 6:40 PM, Alex Mizrahi wrote:
IE> Does anyone actually use derived indices in the current slot
indexing
IE> model?
add-class-derived-index?
yep, we are using them, as they are only way to make some non-trivial
lookups
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