Warp <war### [at] tagpovrayorg> wrote:
>   Object-oriented programming closely matches the thought process of people.
> OOP can be deconstructed into to most basic elements: Concepts and algorithms.
>
>   People think about things conceptually. For example, you can have one pen,
> one car, one dog, and so on.
>
>   Moreover, people use hierarchies of concepts. Some concepts are more
> abstract while other concepts are more concrete. For example, the concept
> of "animal" is more abstract than the concept of "dog" or "cat", which are
> more concrete. Moreover, there's a hierarchical relationship between these
> concepts: A dog is an animal, and a cat is an animal (but a dog is not a cat).

Ah, yes - here we enter the realm of blah that scared *me* away from OOP when I
first came into contact with it:

"WTF - what does *this* crap have to do with *programming*?!"

Honestly, even as a professional SW developer for over a decade now who
definitely prefers OO concepts, I think this is perfect BS.

Despite all claims, I'm convinced this has virtually *nothing* to do with how
normal people *really* think (at least when faced with the task of explaing to
some dumb box how it should *do* something), and has even less to do with OO
*programming*.


David, you hear me? *This* is *not* OOP. This is indeed BS originally from
people leaning on the shallow theoretical side, trying to sell "OO"-labelled
products (compilers, tools, training, consulting, whatever) to people who
haven't experienced the benefits of OOP in practice yet.


*True* OOP is primarily about encapsulation: You highly integrate data
structures and the algorithms operating on them into so-called "objects"; you
precisely define what operations there should be to manipulate the data (for
instance, on a data structure to be used as a stack, you'd primarily want a
"push" and a "pop" operation, plus maybe a few more), and you hide the data
structure from any other code (to the best extent possible with the chosen
language), to prevent the data from being manipulated in any different way.
This is a very powerful tool for keeping track of how and where the data
structures are actually manipulated, so you can more easily change the inner
workings of an object if needs be.

Second, OOP is about "polymorphism": You define operations that should be
possible on various different types of objects (for instance, you might define
a "compute bounding box" operation for all geometric primitives as well as CSG
aggregates) without necessarily doing the same way internally, so they can be
easily processed alongside each other by the same calling code for some purpose
(e.g. get the bounding boxes of all objects) despite any differences in how the
particular operation is actually performed for each type of object.

These, in my eyes, are the most important aspects of OOP. There are others, like
"inheritance" (you might implement part of a new object type by simply referring
to - aka "inheriting from" - a similar object's existing implementation where
applicable, allowing you to easily re-use the existing code) that are of
practical value, too, but I wouldn't rank them as important as encapsulation
and polymorphism.


Strangely enough, inheritence is what the typical blah seems to focus on; on the
other hand, maybe it just feels that way because it's the only thing *really*
unfamiliar to a programmer: Encapsulation, for instance, could be regarded as
modularization driven to the extreme; and as for polymorphism, most programmers
will at least know the underlying problem of how to manage a collection of
elements with different data types. But inheritance? There's really nothing
like this in the world of classical imperative programming, nor does there seem
to be any need for it. Indeed, it is a solution for a problem you won't even
encounter unless you have already entered the realm of OOP. So it's somewhat
ridiculous trying to *introduce* OOP with this.

(I must confess that without this discussion, I would probably try the same
approach to introduce OOP to someone - even though I should know better,
originally having been deterred by this myself; never gave much thought to it
though until now.)

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