From: "Steve Bate" <steve.at.xplanner.org@...>
Sent: Saturday, December 06, 2003 12:30 PM
Subject: RE: [XP] "difficult iterations" challenge


>
> > From: Jeff Grigg [mailto:jeffgrigg@...]
> > >>>Can you give an example of where this seems difficult,
> > >>>but it really isn't?
> >
> > --- Steve Howell <showell@z...> wrote:
> > > Okay, I'll pose one. You have a coffeehouse with a fairly
> > > large menu. You want a system that can calculate the total
> > > bill for each order. Until you put the entire menu on the
> > > system, you can't really use the system, because you still
> > > have to rely on pen and paper. How do you break this
> > > problem down?
> >
> > OK:
> > 1st story: Server types in the total of the food items. System
> > computes tax and total.
> >
> > 2nd story: System computes change.
> >
> > You don't think this provides value?
> > Well, many small diners work just this way.
> >
> > 3rd story: System tracks tips.
> >
> > 4th story: System tracks which servers did which orders.
> >
> > Nth story: System accepts some simple and very common orders.
>
> I don't see any mention of requirements related to stories 2-4.
> This smells a bit like gold plating. After the 1 and Nth stories
> it seems the system would be very awkward to use and error prone.
> The servers now have to know what specific items are supported
> by the system. They must record the other items on paper and
> enter them manually when totalling the order. It would be a
> major training headache considering the "fairly large menu".
> This partial implementation might actually be worse than no
> system at all.
>
> I'm not sure I'd put this in the category of "real standalone
> utility". OTOH, without agreeing to the criteria for "real
> standalone utility" this thread will degrade quickly.

I believe Steve Howell's original set of requirements for the
exercise included entering the amount tendered and calculating
the change due. That's the 2nd story.

The third and fourth weren't in the original exercise, true.

As far as the last one is concerned, though, many places
include the ability to insert orders that aren't on the official
menu. That's what I'd do first, and then add in the menu
items roughly in order of volume. As far as a training
headache, I certainly hope that they're not getting staff
from the local institution for the developmentally disabled!
These things just aren't that hard to learn. The places I've
seen servers have problems have never been on the menu
items: they've always been on the cash and on backing
out mistakes.

However, if this was a realistic situation, I'd put in the
ability to process credit (and debit) cards somewhere
before tracking the servers and tips. There's very little
reason to track either before, and you'll get a lot of
resistance to tracking manual tips: it's a major sore point
with the IRS, among other places.

John Roth