Hi people, A bit late to the party, but I want to provide some info as well.
I think an Article can perfectly respond to a #sell (or #sellQuantity:) message. Depending on the type of application it could know or interact with other objects responsible for Stock for example to provide an estimated delivery date and price. When a customer is not known through some context it could be #sellToCustomer: or #sellToAccount:. But mostly to have a delivery address and make sure payment is done. Not to have a customer do the buying (as an act), that is irrelevant for most (web)shops. There is often no need to have a person like object to fulfil the role of actor (dare I say 'manager') in the object interactions. Objects have behaviour and take on responsibilities of their own. Having a human like object moves responsibilities away from the objects and creates unneeded dependencies between objects. You'll quickly see conditional logic appear in those classes. Kids sometimes understand this way of looking at objects better than we adults. A kid does not find it weird to see a movie or play in which a teapot pours itself or where a CD plays itself. So I do understand that a CD understands #play as a message. Perfectly fine. We do not literally have to represent every physical object and its physical characteristics in our world as objects in our applications. It is the behaviour and responsibilities they posses that counts. (CRC cards are really quite helpful in OO) I highly recommend reading the book Object Thinking by Dave West. For sake of clarity: yes, we are partners in ObjectGuild. See the link to the book below. Don't be put back by the age of the book. http://davewest.us/product/object-thinking/ Cheers, Erik -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html
