*Thanks for getting back to me. I was beginning to wonder which of the 5 ways to interpret the silence :) I think it must be in the genes: ( http://en.wikipedia.org/wiki/Warnock%27s_Dilemma)

Anyway, here is what I've got:

(defmodel cargo-hold () (ship-owner capacity ;; a set of cargo-types (types :cell t :initarg :types :initform nil) ;; cargo-type -> quantity (quantities :cell t :initarg :quantities :initform (make-hash-table))))

(defmodel cargo () ;; a type-id, name and the number of ;; cargo-hold units it takes up (1-3) (type name volume ;; the character-id of the owner of ;; the cargo-hold unless cargo is spaced (holder :cell t :initarg :holder :initform (c-in nil) :accessor holder)

(auth-list :cell t :initarg :auth-list :initform nil :accessor auth-list) (recipient :cell t :initarg :recipient :initform nil :accessor recipient) (stolen :cell t :initarg :stolen :initform (c? (when (member (^holder) (^auth-list)) t)) :accessor stolen) (spaced :cell t :initarg :spaced :initform (c? (when holder t))

:accessor spaced) (delivered :cell t :initarg :delivered :initform (c? (when (eql (^holder) (^recipient)) t)) :accessor delivered)))

The first thing you'll probably notice is that there is no mechanism for the cargo-holds to actually "contain" cargo objects. I know I could do as the "summer" example of the cell-basics doc does, and push them onto a list, and recalculate based on the whole list every time it changes, but I was hoping for something more elegant and efficient. Only one entry in the quantities hash needs to change when an item is added for instance. I thought of having in and out slots (set the slot to a cargo object to add or remove; the other slots do their thing and then clear the in/out slot), but that seems ugly and I wasn't even sure how to pull it off.

And then there is the whole thing with cargo-sets which is closer to what I'd like to do with Cells on the larger scale. Basically what I want is to have a large number of sets and their unions/intersections efficiently accessible anywhere in my code- stuff like "all characters of faction X in sector Y carrying at least one Z in their cargo hold.

I hope this makes my level of understanding more clear. I think I'm probably more prepared for the paradigm shift than most, owing, no doubt, to my long infatuation with Ted Nelson's ZigZag.

~Michael Warnock Guild Software Inc. *I've Ive Iver Ivie IV Edit... Revert to "i've" def model def-model defamed daffodil deformed Edit... Ignore all Add to dictionary unitary intake interj Anitra Unitas Edit... Ignore all Add to dictionary uniform inform infirm uniformer interim Edit... Ignore all Add to dictionary unitary intake interj Anitra Unitas Edit... Ignore all Add to dictionary uniform inform infirm uniformer interim Edit... Ignore all Add to dictionary def model def-model defamed daffodil deformed Edit... Ignore all Add to dictionary unitary intake interj Anitra Unitas Edit... Ignore all Add to dictionary uniform inform infirm uniformer interim Edit... Ignore all Add to dictionary accessory access or access-or access access's Edit... Ignore all Add to dictionary ACTH Ruth auto Edit... Ignore all Add to dictionary unitary intake interj Anitra Unitas Edit... Ignore all Add to dictionary ACTH Ruth auto Edit... Ignore all Add to dictionary uniform inform infirm uniformer interim Edit... Ignore all Add to dictionary assessor access or access-or accessory access Edit... Ignore all Add to dictionary ACTH Ruth auto Edit... Ignore all Add to dictionary unitary intake interj Anitra Unitas Edit... Ignore all Add to dictionary uniform inform infirm uniformer interim Edit... Ignore all Add to dictionary assessor access or access-or accessory access Edit... Ignore all Add to dictionary unitary intake interj Anitra Unitas Edit... Ignore all Add to dictionary uniform inform infirm uniformer interim Edit... Ignore all Add to dictionary ACTH Ruth auto Edit... Ignore all Add to dictionary assessor access or access-or accessory access Edit... Ignore all Add to dictionary unitary intake interj Anitra Unitas Edit... Ignore all Add to dictionary uniform inform infirm uniformer interim Edit... Ignore all Add to dictionary assessor access or access-or accessory access Edit... Ignore all Add to dictionary unitary intake interj Anitra Unitas Edit... Ignore all Add to dictionary uniform inform infirm uniformer interim Edit... Ignore all Add to dictionary El Eal Erl eel ell Edit... Ignore all Add to dictionary assessor access or access-or accessory access Edit... Ignore all Add to dictionary Zigzag Zigzags Zigzag's Edit... Ignore all Add to dictionary Warlock Wank Warwick Wonk Bannock Edit... Ignore all Add to dictionary