Hum, on 05 June 2012 - 16:22, said:
didn't really understand it -- oh well.
Programmers take everything literally as our instructions to the device are literal.
So the condition as expressed literally was to bring back 6 cartons of milk if the store had eggs in stock.
A "normal" person would interpret it to mean bring back 6 eggs if they have any eggs and one carton of milk. As they would do what makes the most sense even if that isn't the literal request.