Tuesday, May 1, 2018

Misunderstanding OO Programming

Read this. Goodbye, Object Oriented Programming

I like this because parts of it are wrong, and parts are based on peculiarities of specific languages which aren’t problems in other languages.

The “wrong” things are on a spectrum. At one end are things almost right. The other end is hoped-for things which — frankly — were never true.

The most important piece of nonsense is class-level reuse across projects. Class-level reuse in a new project was not a thing in OO programming. The monkey-banana-jungle “problem” only exists in a strange world were someone made up the idea of single classes being reused in isolation. The rest of us knew the scope of reuse was within a project or a narrow family of projects aimed at a single problem domain.

"Utility" classes that could be reused and generic data structures were always available as frameworks and libraries. Things built to solve a specific problem were going to be tailored to the problem. Most OO designers knew this and knew that making something generic would be hard. Making something reusable and installable by others was even harder. (Especially in compiled languages where you wanted to hide intellectual property by keeping the source secret.)

The "OO promised me reuse and lied" is a misstatement. Please rephrase this is "I imagined there could be class-level reuse and discovered it was hard."

Multiple inheritance does work in a number of languages, so I’ll skip the complaints centered on single inheritance.

I don't fully understand the complained about encapsulation. There are lots of books on separating interface from implementation to more fully isolate implementation details. If references need to be treated more opaquely, there are lots of techniques for this. It’s not broken. Indeed, it’s really well understood. ("But I won't want to introduce wrapper classes to insulate the references." Sigh. That's how it's done.)

I think the "references leak details about encapsulation" requires rephrasing as "I imagined some kind of perfectly isolated programming where references were not usable in spite of me making them usable." Or perhaps "I wish references had special treatment to make them not work as references except in a limited context which I get to imagine."

The polymorphism complaint appears to be “okay, this actually works.”  I guess. Or. “There are other ways to do this in other languages.” I'm sure it's an important point, but I can't quite discern what OO principle is allegedly broken here.


No one was lied to. If someone was "burned" by some OO hype, I’d like to see the actual quote of the actual hype. The “I was told there would be X”, requires some substantiation.

And. Stop griping about encapsulation. When the source is available (as it is in many languages) there's no enforcement other than public shaming.

Also. Use Python. Most of the original post seems to be complaints about C++ weirdness.