[gruseom]

You believe this, but you've given no reason to believe it other than the dogma you favor. The old-fashioned procedural systems I've seen with global state and the like were actually easier to understand than the convoluted object systems with which they were often replaced. Your comment is exactly the kind of thing that people who are enthralled with a paradigm say. But the "worst Enterprisey mess of Java" that you blithely invoke is... really bad, actually, as bad as anything out there. You're assuming that paradigm shifts constitute progress. I offer an alternate explanation for why paradigms may shift: because the new generation wants to feel smarter than the old one.

[hackinthebochs]

OO enterprisey mess is strictly better than global state ridden spaghetti code. The hard part with enterprisey code is that the code performing the action is hidden under layers of abstraction. The bootstrapping cost is much higher here because you have to put more abstractions in your head before you can understand a particular bit of functionality. This is a different sort of complexity than the global state spaghetti.

With the global state code you have to understand the entire codebase to be sure who exactly is modifying a particular bit of state. This is far more fragile because the "interaction space" of a bit of code is much greater. The dangerous part is that while you must understand the whole codebase, the code itself doesn't enforce this. You're free to cowboy-edit a particular function and feel smug that this was much easier than the enterprisey code. But you can't be sure you didn't introduce a subtle bug in doing so.

The enterprisey code is better because it forces you to understand exactly what you need to before you can modify the program. Plus the layered abstractions provide strong type safety to help against introducing bugs. Enterprisey code has its flaws, but I think its a flaw of organization of the code rather than the abstractions themselves. It should be clear how to get to the code that is actually performing the action. The language itself or the IDE should provide a mechanism for this. Barring that you need strong conventions in your project to make implementations clear from the naming scheme.

[gruseom]

This sounds like ideology to me. You can never be sure you didn't introduce a subtle bug, you can never force someone to understand what they need to, and interactions between objects can be just as hard to understand as any other interactions.

I agree that a project needs strong conventions, consistently practiced. See Eric Evans on ubiquitous language for the logical extension of that thinking. But this is as true of OO as anywhere else.

[hackinthebochs]

First off, apologies for seemingly badgering you in various threads in this post. I don't usually look at usernames when replying so it was completely by accident.

>interactions between objects can be just as hard to understand as any other interactions.

While this is true, there are strictly fewer possible interactions compared to the same functionality written only using primitives. To put it simply, one must understand all code that has a bit of data in its scope to fully understand how that bit of data changes. The smaller the scopes your program operates in, the smaller the "interaction space", and the easier it is to reason about. Class hierarchies do add complexity, but its usually well contained. It adds to the startup cost of comprehending a codebase which is why people tend to hate it.

[gruseom]

That's hilarious. Well, you're welcome to "badger" (i.e., discuss) anytime. It's I who should apologize for producing every other damn comment in this thread.

In my experience, classes don't give the kind of scope protection you're talking about. They pretend to, but then you end up having to understand them anyway. True scope protection exists as (1) local variables inside functions, and (2) API calls between truly independent systems. (If the systems aren't truly independent, but just pretending to be, then you need to understand them anyway.)

[hackinthebochs]

You're right that the scope protection I'm talking about isn't as clear cut when it comes to classes. Design by contract is an attempt to address this. Client code can only refer to another object through a well-defined interface. Thus your limited scope is enforced by the type system itself. Furthermore, much of this discussion is about perception of complexity rather than actual complexity.

In python you can access any classes internals if you're persistent enough. However, the difficulty in doing so and the convention that says that's bad practice gives the perception of a separation, thus one does not need to be concerned about its implementation. It lowers the cognitive burden in using a piece of functionality.

Haven't you noticed this yourself? A simpler interface is much easier to use than a more complicated one. If you're familiar with python, perhaps you've used the library called requests, its a pythonic API for http reqeusts. Compare this to the core library API using urllib2. The mental load to perform the same action is about an order of magnitude smaller with requests than urllib2, and its because there are far more moving parts with the latter.

My contention is that if bits of data and code are exposed to you, it is essentially a part of the API, even if you never actually use it. You still must comprehend it on some level to ensure you're using data it can access correctly, aka interaction space (I feel like I'm selling a book here).