Re: question about informal protocols
On Nov 20, 2009, at 12:22 PM, Jens Alfke wrote: > > On Nov 20, 2009, at 12:09 PM, Michael de Haan wrote: > >> Does the, in your opinion, "optional" addition pretty much replace >> categories as a whole, or is there still a role for them? > > It replaces informal protocols. There are many other uses for categories, like > > * Breaking a class implementation across several source files > * Declaring private/internal class methods that a few other classes are > allowed to call > * Declaring some of a class's methods in other headers (ones that only make > sense in the context of that other header) > * Adding methods to a pre-existing framework class Not to overlook the all-important AppKit and UIKit 'Additions' to their respective Foundation Frameworks . . . Cheers, . . . . . . . .Henry ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: question about informal protocols
On Nov 20, 2009, at 12:19 PM, David Duncan wrote: > On Nov 20, 2009, at 12:09 PM, Michael de Haan wrote: > >> Did not see that it was deprecated, but will take your lead and convert them >> to that. Does the, in your opinion, "optional" addition pretty much replace >> categories as a whole, or is there still a role for them? > > > The addition of @optional and @required to Protocols is meant to replace the > need for Informal Protocols. Categories are still very useful for adding > functionality to a class, as Protocols only allow you to create an interface, > not an implementation. > -- Good...because the example makes much use of both categories and extensions... :-) Thanks David. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: question about informal protocols
On Nov 20, 2009, at 12:09 PM, Michael de Haan wrote: > Does the, in your opinion, "optional" addition pretty much replace categories > as a whole, or is there still a role for them? It replaces informal protocols. There are many other uses for categories, like * Breaking a class implementation across several source files * Declaring private/internal class methods that a few other classes are allowed to call * Declaring some of a class's methods in other headers (ones that only make sense in the context of that other header) * Adding methods to a pre-existing framework class —Jens___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: question about informal protocols
Le 20 nov. 2009 à 21:09, Michael de Haan a écrit : >> >> >> The usual way is to NOT implements the NSObject category and test if the >> delegate implements the method using -respondsToSelector: >> But this way works too if you don't want to have to test before sending your >> message. >> >> Anyway, informal protocols are "deprecated" in favor of @protocol with >> @optional method. >> >> >> -- Jean-Daniel >> >> >> >> > > > Did not see that it was deprecated, but will take your lead and convert them > to that. Does the, in your opinion, "optional" addition pretty much replace > categories as a whole, or is there still a role for them? > They are not formally deprecated (that's why I used quotes), but Apple replaced most if not all Cocoa informal protocols in 10.6 and there is no reason to use them anymore. @optional replaces categories used as informal protocol, but this is not the only usage for categories. They are very useful if you want to add a method to an existing class. -- Jean-Daniel ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: question about informal protocols
On Nov 20, 2009, at 12:09 PM, Michael de Haan wrote: > Did not see that it was deprecated, but will take your lead and convert them > to that. Does the, in your opinion, "optional" addition pretty much replace > categories as a whole, or is there still a role for them? The addition of @optional and @required to Protocols is meant to replace the need for Informal Protocols. Categories are still very useful for adding functionality to a class, as Protocols only allow you to create an interface, not an implementation. -- David Duncan Apple DTS Animation and Printing ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: question about informal protocols
> > > The usual way is to NOT implements the NSObject category and test if the > delegate implements the method using -respondsToSelector: > But this way works too if you don't want to have to test before sending your > message. > > Anyway, informal protocols are "deprecated" in favor of @protocol with > @optional method. > > > -- Jean-Daniel > > > > Did not see that it was deprecated, but will take your lead and convert them to that. Does the, in your opinion, "optional" addition pretty much replace categories as a whole, or is there still a role for them? ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: question about informal protocols
Le 20 nov. 2009 à 20:46, Michael de Haan a écrit :
> I am working through an example in Buck/Yacktman's book that uses an
> informal protocol.
>
> In the interface of of a custom class, it is declared as such.
>
>
> #import
>
>
> @interface MyShapeEditorDocument : NSDocument
> {
>ivars
> }
> @end
>
>
> @interface NSObject(MYShapeEditingDocEditor)
>
>
>
> -(void) controllerDidEndEditing;
> @end
>
>
> In the implementation file it is defined, twice, thus.
>
>
> @implementation NSObject(MYShapeEditingDocEditor)
>
> -(void) controllerDidEndEditing
> {
>
> }
> @end
>
> and in the main body of the code, thus.
>
>
> @implementation MyShapeEditorDocument
>
>
> -(void) controllerDidEndEditing
> {
>[[self myView] setNeedsDisplay: YES];
>[[self table] reloadData];
> }
>
>
> Apple's docs say: "When used to declare a protocol, a category interface
> doesn’t have a corresponding implementation. Instead, classes that implement
> the protocol declare the methods again in their own interface files and
> define them along with other methods in their implementation files."
> (http://developer.apple.com/mac/library/documentation/cocoa/Conceptual/ObjectiveC/Articles/ocProtocols.html#//apple_ref/doc/uid/TP30001163-CH15-TPXREF147)
>
>
> What I am not following is the seemingly double definitions. From the docs,
> it would seem that implementation is a 2 step process, not a 3 step as above,
> even though this is clearly correct. What is the essence that I am missing?
The usual way is to NOT implements the NSObject category and test if the
delegate implements the method using -respondsToSelector:
But this way works too if you don't want to have to test before sending your
message.
Anyway, informal protocols are "deprecated" in favor of @protocol with
@optional method.
-- Jean-Daniel
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