I have been looking through sample code provided by Apple and stumbled upon something interesting I've not learned about. In a subclass in the .m file, there are multiple sections declared with @implementation. The last one is the usual @implementation I expect - the class implementation where all the code goes, but above that are a couple short implementations that each define a single method. They are declared in this format: @implementation ClassName (Convenience). The method defined within is in the same format as other methods, but they are prefixed with aapl_. After each @implementation definition follows @end, of course. The way these methods are called is to create an instance of ClassName then call the method as you would with the standard API: [anInstance aapl_thisInterestingMethod:aParameter];
So this appears to be a way to add a method to a class without creating a category, you call it with an instance of the class, and it's only specific to this file. You can use self to refer to the calling argument.
My question are:
- Is there more to it than that?
- Why is (Convenience) appended to the end?
- Is the
aapl_prefix added simply only to indicate this isn't part of the standard API but instead our own method? - Why is this better than defining a method as you normally would, accepting in the calling argument as a regular argument? For example:
[self anInterestingMethod:myInstance withParameter:aParameter]; - What are these types of methods/implementations called and what else should I know about them?
EDIT: This question is not at all related to the question this is marked as a duplicate of... @interface is not @implementation