[13ren]

Complex and confusing problems can be tackled by breaking them into modules, with interfaces between. Objects are one way of doing it.

Each object wraps up a program. The program's global variables become variables of the object. The program's functions become functions of the object. The public functions are the interface of the object (an interface is the part of a module that interacts with other modules, like the surface of an object). So basically, you have the inside of the object, and the outside (surface).

Think of it as support for the modules that you already wanted, that seem to be naturally present in the problem, or in how you naturally want to divide it up and think about it. That is, use OO to support your conception, instead of a priestly template to mold yourself into. Tools are good slaves, poor masters. If you follow your conception, you will make mistakes - but those mistakes will belong to you, and so you will learn from them.

Using objects for modularity does not work well for every case (e.g. I think parsing works better in the old-fashioned style).

OO is nothing special. There's no wonderful mysterious secret. It doesn't even have a precise definition that everyone agrees on. It's just a tool. Inheritance and polymorphism are grossly overrated, but presented as a quasi-religious AI solution-to-everything - but are useful in some cases (e.g. great for windows/GUIs). There's also a danger of having overly theoretical modules - the "spaces" you mention. Be problem-driven. What does the problem need?