An Objective-C pattern for making sum types - ExampleTestsTestTransformExample.m

ExampleTestsTestTransformExample.m

#import "Example.h" // https://gist.github.com/hborders/e00d7ff965ca8f8df8f7e762a2269efb
#import "ExampleSwitcher.h" // https://gist.github.com/hborders/f378b4e0d0f1d74ff7c8149cb04c6268
#import "ExampleFoo.h" // https://gist.github.com/hborders/094f05d932b3d7a1e389184ba525b0c3
#import "ExampleBar.h" // https://gist.github.com/hborders/f1c231a89de11157adf46ee85880733a

static NSNumber * _Nonnull transformExample(Example * _Nonnull example) {
    return [ExampleSwitcher<NSNumber *> nonnullValueFrom:example
                                               switchFoo:^NSNumber * _Nonnull (ExampleFoo * _Nonnull foo_) {
                                                   return @(foo_.f.length + foo_.g.length);
                                               }
                                                     bar:^NSNumber * _Nonnull (ExampleBar * _Nonnull bar_) {
                                                         return @(bar_.b + bar_.c);
                                                     }];
}

- (void)testTransformExample {
    Example * _Nonnull fooExample = [[ExampleFoo alloc] initWithF:@"foo"
                                                                g:@"goo"];
    Example * _Nonnull barExample = [[ExampleBar alloc] initWithB:2
                                                                c:3];
    
    NSLog(@"transformed Foo: %@", transformExample(fooExample)); // transformed Foo: 6
    NSLog(@"transformed Bar: %@", transformExample(barExample)); // transformed Bar: 5
}