optional parameters

Question

I have taken (with the authors permission on the site) a wrapper class for writing fetch requests to my Core Data stack.

The guy who wrote it says it has "optional parameters" and I wondered what this meant.

Anywho, the static methods are written as such...

+(NSMutableArray *) searchObjectsFromContext
    : (NSString*) entityName
    : (NSPredicate*) predicate
    : (NSString*) sortKey
    : (BOOL) sortAscending
    : (NSManagedObjectContext *) managedObjectContext

I have been running it and passing "nil" into the unneeded params. Is this the correct thing to do?

Also, is there a significance to the fact that there is no extra method text between the colons?

Thanks for any help

Oliver

Answer 1

Optional parameters are available in VB (and some other languages) but not C#. C# forces you to overload functions.

You can pass "default" values to the optional parameters if you like. As long as you know how the function will respond, I don't see how this will hurt anything.

EDIT: I just read your iphone tag.... sorry! I don't know how relevant my answer is to you in that regard

Answer 2

It's impossible to say if passing 'nil' is the correct thing to do without reading the documentation or examining the source code. It's probably correct, though, as that is standard behavior in most classes.

Creating method parameters without associated text (as you see in your posted code) is perfectly legal... but it's also perfectly ugly and you lose all the benefits of Obj-C's verbosity. There's absolutely no reason to write code like that, it only serves to make your classes more difficult to use.