Its comforting to see that other have the same reaction as me - I agree with the sentiment that you send messages to objects - and the naming of those messages and their context is important.

and CD.buy - is at least a message to an object but as others have commented, it  highlights flaws in the context or modelling as it just doesn't read right. I'd model it different too.

Phew, I'm not losing it....

Tim

On Fri, 16 Apr 2021, at 2:44 PM, Russ Whaley wrote:
Wow, I must be missing a whole lot of context in that discussion...  (instant reaction as well, lol)

- a product (CD, book, etc.) does not 'buy' - it can be bought, sure, but it has no buying action.  Even in another context a CD does not 'play'... aMusicPlayer.play(aCD).
- However, a customer can 'buy' a product... 
  • customer.buy(aCD) -or-
  • customer.addToCart(aCD)
  • customer.checkOut(aCart)
  • Invoice.new(aCart), etc. 
- ... but the CD doesn't DO anything. 

- I get the idea that different products might have different behaviour when they are 'bought' - but these are, in this example, fulfillment - not the 'buy' action... 
  • aCDstream might be set for download
  • aCDphysical might be set to physically pull off a shelf and ship
  • aCDcare might send an email on warranty, whatever... but let's name it better than 'buy' :)
Tim, thanks for the link - I'm always trying to expand my thinking about object modeling - discovering cool ways/things others are thinking about...  Now I have to go dust off all my old POS (point of sale, not piece of s#&t) code and see how poorly I may have modeled those environments!!

Thanks for the morning diversion!  Cheers.

On Fri, Apr 16, 2021 at 8:53 AM Esteban Maringolo <emaringolo@gmail.com> wrote:
I saw a tweet about that, and I think that the example is misleading, maybe intentionally so.

I don't think anybody would model it that way, in any case you'd have aProduct.buy() or aProduct.addToCart(aCart). 

If you think it with the typical dog.bark() it certainly makes more sense than bark(dog).

Regards!

Esteban A. Maringolo


On Fri, Apr 16, 2021 at 5:20 AM Tim Mackinnon <tim@testit.works> wrote:
Hi guys - someone pointed out this article from a UK colleague which seems to be causing a flurry of discussion - but I always like the insights of this group. I had an instant reaction when I read it - but curious what people here think in 2021.


Tim


--
Russ Whaley
whaley.russ@gmail.com