Why you need it

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, EasyTuple, it can group multiple values in a better way.

How to use it

You can use the macro EZTuple to create a tuple, and it supports generics. Like this:

EZTuple3<NSNumber *, NSString *, NSDictionary> *tuple = EZTuple(@1, @"string", nil);

EZTuple3 means there are 3 items in this tuple. So EZTuple6 is 6 item. There are 20 classes from EZTuple1 to EZTuple20 support you to use.

The maximum capacity of EZTuple 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.

You have serval ways to get and set values:

EZTuple3<NSNumber *, NSString *, NSDictionary> *tuple = EZTuple(@1, @"string", nil);
// use the unpack macro
EZTupleUnpack(NSNumber *a, NSString *b, NSDictionary *c, EZT_FromVar(tuple));
NSLog(@"first:%@, second:%@, last:%@", a, b, c);
// 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
BOOL hasNil = NO;
for (id value in tuple) {
    NSLog(@"%@", value);
    if (value == nil) hasNil = YES;
    tuple.first = @3 // will throw an exception!
}
// hasNil -> YES

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).

EZTuple supports NSCopying protocol. You can easily copy them if you need.

Named tuples

The tuple classes from EZTuple1 to EZTuple20 only have properties first, second, etc. You may need to give the properties custom names. Named tuple can help you.

Each named tuple is a class. So you may declare it like this:

// File TestNamedTuple.h or the other header

@import EasyTuple;

// Define a macro table with your tuple name concating 'Table'
#define TestNamedTupleTable(_) \
_(NSString *, string) \
_(NSNumber *, number) \
_(NSDictionary *, dictionary)

// Declare your class which is your tuple name
EZTNamedTupleDef(TestNamedTuple)

You should implement the class because it is a real class. You may implement it like this:

// File TestNamedTuple.m or the other .m file
#import "TestNamedTuple.h"

// Implement your class
EZTNamedTupleImp(TestNamedTuple)

Now you can use your named tuple like a normal class:

- (void)anyMethod {
    TestNamedTuple *tuple = TestNamedTupleMake(@"str", @15, @{@"key": @"value"});
    tuple.string = @"new";
    NSLog(@"property number is %@", tuple.number);
}

There is generic inside the property type? Don't worry, it can support like this:

#define TestNamedTupleWithGenericTable(_) \
_(NSArray<T> *, arr) \
_(NSDictionary<K, V> *, dic);

EZTNamedTupleDef(TestNamedTupleWithGeneric, T, K, V)

Features

• EZTuple macro create a tuple quickly
• ordinal number properties
• subscripts accessing
• for-in accessing
• NSScopy protocol supporting
• drop some item or take some item
• join two tuples
• convert a tuple to an array or convert an array to a tuple
• declare named tuple

Advantages

Compare to NSArray / NSDictionary, EZTuple has the following advantages:

• Supports generics for EACH element
• Key-Value Observable
• Supports nil
• Access elements via ordinal numbers and last

Acknowledgement

This library is highly inspired by the macro techniques in libextobjc.

Example

To run the example project, clone the repo, and run pod install from the Example directory first.

Requirements

Installation

EasyTuple is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod "EasyTuple"

Author

WilliamZang, [email protected]

JohnnyWu, [email protected]

ValiantCat, [email protected]

License

EasyTuple is available under the MIT license. See the LICENSE file for more info.