Re: Objective-C and it's future
Re: Objective-C and it's future
- Subject: Re: Objective-C and it's future
- From: Rob Ross <email@hidden>
- Date: Fri, 7 Jul 2006 18:15:57 -0700
NSString *str = [[NSData alloc] init];
because both `NSData' and `NSString' have `init' methods, and
`init' methods return an object of type `id', which is NOT
statically typed.
This looks like the kind of bug that would be easy to make,
especially with class names that are very similar. I guess you won't
find out until you send the object a message at runtime that it can't
process; then you'd have to hunt back through the stack trace to see
how you declared the object. I suppose in practice, it wouldn't be
that hard to debug this kind of error.
For more egregious violations, like for example ...
Cat *cat = [[Cat alloc] init];
[cat bark];
... the compiler will throw up a warning and tell you that `cat'
may not respond to the selector `bark'.
Well I'm glad at least it does that!
So my understanding is you can have the best of both worlds. Or
have I misunderstood something?
Not quite. Objective-C is pretty well entrenched in the runtime.
You have to remember that you're NOT actually "calling a method"
when working with Objective-C objects. You are sending them
messages. Think about it this way. If language objects are people,
then C++ objects are basically puppets. You don't tell them to do
something; you just pull the string, and they do it. Objective-C
objects are more independent. You TELL them that you'd like
something done, and they'll do it if they can.
--
That's interesting, because I remember a point long ago when I was
first learning OO programming (in C++), that I understood the concept
of "message passing", but that C++ didn't really implement that (nor
does Java): you're invoking a method, not passing a message. I was
always puzzled by the definition because the languages I used didn't
really seem to behave as described. It's nice to finally meet a
language that does what I intuitively understood "message passing" to
be.
Rob
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