Sometimes you may need to return multiple values other than just one. In these cases, you can use a pointer, like NSError **, or you can put them into an array or a dictionary, or straightforward, create a class for it. But you have another choice now, ZTuple, it can group multiple values in a better way.
You can use the macro ZTuple to create a tuple, and it supports generics. Like this:
ZTuple2<NSNumber *, NSString *> *tuple = ZTuple(@1, @"string");You have serval ways to get and set values:
ZTuple2<NSNumber *, NSString *> *tuple = ZTuple(@1, @"string");
// use the unpack macro
ZTupleUnpack(NSNumber *a, NSString *b, Z_FromVar(tuple));
NSLog(@"first:%@, second:%@", a, b);
// use ordinal numbers like first, second
tuple.first;
tuple.first = @5;
// use last
tuple.last;
tuple.last = @"last";
// use subscript
tuple[0];
tuple[0] = @"s";
// iteration
for (id value in tuple) {
NSLog(@"%@", value);
tuple.first = @3 // will throw an exception!
}The lastof the tuple is an alias of the "last element", in the sample code above, it is equivalent to second.
All the elements inside the tuple are Key-Value Observable. If you observe second and last, both callbacks will be invoked if you changed second (or last).
ZTuple supports NSCopying protocol. You can easily copy them if you need.
The maximum capacity of ZTuple is 20. It is big enough in most cases. If you really need something larger than that, an array or a dictionary might be a better choice at the moment.
Compare to NSArray / NSDictionary, ZTuple has the following advantages:
- Supports generics for EACH element
- Key-Value Observable
- Supports
nil - Access elements via ordinal numbers and
last
This library is highly inspired by the macro techniques in libextobjc.
To run the example project, clone the repo, and run pod install from the Example directory first.
ZTuple is available through CocoaPods. To install it, simply add the following line to your Podfile:
pod "ZTuple"WilliamZang, [email protected]
JohnnyWu, [email protected]
ZTuple is available under the MIT license. See the LICENSE file for more info.