Date: Mon, 19 May 2008 19:18:30 -0400
From: Andy Lee <[EMAIL PROTECTED]>
[...] When you are accessing only the public API for a class, C#'s
extension methods provide the same sort of syntax, but via static
methods that the compiler handles so as to make them look like they
are part of the original class.
Interesting. When you say static methods, do you mean methods that
cannot access instance internals?
I mean "static" in the sense of: a method not associated with a
specific object instance.
What does self (or this, or
whatever) refer to in those methods?
Nothing. It's not valid.
As Philippe correctly pointed out, this is not quite the same as
categories in Objective-C. Only code compiled with extension methods
will wind up using them, and they can't do things like override
existing virtual methods.
But personally, it makes me nervous to have a language that allows
the implementation of a class to change according to other code not
related to the class. It's one thing if you're just adding a method
that you want to use somewhere else. But in Objective-C you can also
add a method that overrides a base class method, or would not
normally exist in the class but which has meaning to some other code
that might check for it.
Powerful? Yes. But I'm reminded about the classic joke about how
you shoot yourself in the foot with different programming languages.
I _like_ that in C#, you can't modify an existing class, except as a
syntactical shorthand.
If I had ever found myself banging my head against the wall or
wasting an exorbitant amount of time trying to get around the lack of
such features in other languages, I might be more inclined to find
them worth the trade-off in increased ways to shoot yourself in the
foot. But I haven't, so I'm not.
Obviously, other people's mileage may vary, including your own. But
I really REALLY think it would be worthwhile for the existing Cocoa
community, and especially the experts, to try to look at the issue
from this point of view once in awhile.
I don't go around telling you guys that you're crazy for wanting to
use Objective-C and even liking it. I find it condescending and
abusive that rather than those who are having trouble adjusting, or
who simply find the language not exactly to their liking, being
offered some sympathy instead those people are basically told "well,
you just haven't learned enough about Objective-C", or "you obviously
don't know anything about OOP", or "only the true believers are
worthy to write Mac software", or any of the numerous other
variations on that theme.
And no, not all responses are long those lines. But there's
certainly no shortage of those kinds of sentiments.
I can't speak for others, but for my own part, my goal isn't to
convince everyone that Objective-C is bad. My goal is to try to
express my own personal views of the language and why I feel the way
I do, as a way of trying to get someone, _anyone_ to have just a
smidgen of empathy for a person like me who does not necessarily find
the Kool-Aid particularly to his liking.
And one last time: it's NOT the language that really causes me
distress. The things I've spent an inordinate amount of time
discussing really are minor annoyances, easily dealt with. I don't
_have_ to have a safe language, I just happen to like that better.
If I could pick three things that I could change about Mac software
development, and with a wave of a magic wand fix them instantly,
there's nothing in Objective-C that would make that list.
Pete
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