Re: What is the equivalent of a C++ pure-virtual function in Objective-C?
Re: What is the equivalent of a C++ pure-virtual function in Objective-C?
- Subject: Re: What is the equivalent of a C++ pure-virtual function in Objective-C?
- From: Jean-Daniel Dupas <email@hidden>
- Date: Mon, 12 Jan 2009 09:33:05 +0100
Le 12 janv. 09 à 03:29, Graham Cox a écrit :
On 12 Jan 2009, at 1:20 pm, Michael A. Crawford wrote:
I want to force derived classes to implement a given interface
without provided a default implementation. Does the concept exist
in Objective-C (I'm almost sure it does)? If so, what does the
syntax look like?
The nearest thing to pure virtual methods is a formal protocol,
declared using the @protocol directive.
file:///Developer/Documentation/DocSets/com.apple.ADC_Reference_Library.CoreReference.docset/Contents/Resources/Documents/documentation/Cocoa/Conceptual/ObjectiveC/Articles/chapter_7_section_6.html
A class that "conforms to" the formal protocol is required to
implement the methods of the protocol.
Just for the record. Mac OS 10.5 introduced two new keywords to define
methods in a protocol:
@required
@optional.
A class that "conforms to" the formal protocol is required to
implement the methods marked as required of the protocol.
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