alt Hacker NewsThen you're going to be pleasantly surprised, because composition is actually a genuine OOP technique and Sandi Metz advocates for exactly this kind of sane OOP focused on encapsulation and objects making sense, instead of masturbating with class hierarchies.
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What’s funny is I did composition for a take home project when interviewing at a place and they said the approach was too complicated and failed me for it. They wanted multiple inheritance instead. Fair enough. Their codebase probably had a lot of it and my not showing it probably told them I didn’t understand it.
I used to work at a flask shop that did views with 3-5 or more inherited classes. Nobody could really follow how everything worked. It was insane.
Anyways yeah give me composition and flat classes all day long.
But I've read the book, and her solution to the "bottles of beer" problem involves encoding all the logic into an elaborate class hierarchy!
I'm not rabidly anti-OOP, but the point at which I turn against it is when the pursuit of "properly" modelling your domain with objects obscures the underlying logic. I feel like this book reaches that point. This is her stance on polymorphism:
> As an OO practitioner, when you see a conditional, the hairs on your neck should stand up. Its very presence ought to offend your sensibilities. You should feel entitled to send messages to objects, and look for a way to write code that allows you to do so. The above pattern means that objects are missing, and suggests that subsequent refactorings are needed to reveal them.
Absolutely not! You should not, as a rule, be replacing conditional statements with polymorphic dispatch. Polymorphism can be a useful tool for separating behaviour into modules, but that trade-off is only worthwhile when the original behaviour is too bloated to be legible as a unit. I don't see an awareness of that trade-off here. That's my problem.