3 ms·

DRY is also not the goal.

• rkangel 4y ago
  It's not a million miles from it though. If you start from DRY as an approach to OO design you'll produce something vaguely reasonable and be close enough to where you want to be that you can learn the differences.
  • bborud 4y ago
    I should have been a bit more precise. There are essentialy two ways to approach DRY in OO. One is to inherit implementation, which isn't the best way to go about things since it leads to more brittle code. The other way is to make sensible use of polymorphism and composition. There are aspects of DRY that are worth pursuing (like reducing the number of places you need to get things right) and some that aren't worth pursuing (thinking you reduce the amount of work by re-using code heavily). For code to be reusable you have to be sure that developers only have to care about its interface. Implementation inheritance often doesn't do that. I've worked on projects with people who were obsessed with DRY and made heavy use of implementation inheritance, and the projects inevitably needed extra work to untangle a brittle mess with lots of surprising behaviors.
    • rkangel 4y ago
      Yes, to be fair the simplest advice to new programmers about how to use inheritance should be "don't". Aggregation good, polymorphism good, inheritance bad more often than not.