Re: why Obj-C
Re: why Obj-C
- Subject: Re: why Obj-C
- From: Thomas Lachand-Robert <email@hidden>
- Date: Tue, 9 Apr 2002 16:03:31 +0200
Le mardi 9 avril 2002, ` 02:36 , Marcel Weiher a icrit :
On Tuesday, April 9, 2002, at 12:32 Uhr, Ondra Cada wrote:
On Tuesday, April 9, 2002, at 03:28 , John C. Randolph wrote:
foo = [[MyClass alloc] initWithSomeOtherObject:[OtherClass randomObject]
];
foo=MyClass->alloc()->initWithSomeOtherObject(OtherClass->randomObject()
)
;
Sure, this works, but let's see what the good doctor has to say on this
subject:
[snip]
I find this observation to be exactly on the mark. Yes, it is probably
odd at first, but for some reason the Objective-C syntax seems to allow
more complex expressions to be handled more clearly, similar to the way
that Objective-C allows us to handle greater program complexity more
clearly.
Actually this doesn't really work and is certainly bad C++ style.
If you write
foo = MyClass->alloc()->initWithSomeOtherObject(OtherClass()->randomObject(
))
the programm will crash if any of the function returns a null pointer.
For this reason, a good C++ programmer will do something like:
MyClass *p = MyClass->alloc();
if (p) {
Other *q = OtherClass();
if (q) {
p-> initWithSomeOtherObject( q->randomObject() );
//continue...
}
}
This means that basically you cannot nest calls to dynamic objects in C++,
except being imprudent. There is a similar problem in Java.
One of the great features of Obj-C is that it permit calls to null
pointers. This is a strong requirement for nesting calls. So the probem is
not really related to the syntax of these languages.
Thomas Lachand-Robert
********************** email@hidden
<< Et le chemin est long du projet ` la chose. >> Molihre, Tartuffe.
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