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void Events1(NSString * identifier, void (^handler)());
void Events2(NSString * identifier, void (^)());
@implementation NSArray (WWDC)
- (NSArray *)map:(id (^)(id))xform {
id result = [NSMutableArray array];
for (id elem in self)
[result addObject:xform(elem)];
return result;
}
- (NSArray *)collect:(BOOL ( ^ )(id))predicate {
id result = [NSMutableArray array];
for (id elem in self)
if (predicate(elem))
[result addObject:elem];
return result;
}
- (void)each:(void (^)(id object))block {
[self enumerateObjectsUsingBlock:^ (id obj, NSUInteger idx, BOOL *stop) {
block(obj);
}];
}
// corner case: block literal in use with return type
id longLines = [allLines collect:^ BOOL (id item) {
return [item length] > 20;
}];
// corner case: block literal in use with return type
id longLines = [allLines collect:^ BOOL* (id item) {
return [item length] > 20;
}];
@end
nestedMethodCall(methodCall(^ BOOL * (id item) {
NSLog(@"methodCall")
}));
nestedMethodCall(
arg1,
methodCall(^ NSString * (id item) {
NSLog(@"methodCall")
}));
nestedMethodCall(
arg1,
methodCall(^ {
NSLog(@"methodCall")
},
arg2)
);
nestedMethodCall(
methodCall(^ {
NSLog(@"methodCall")
})
);
// 1. block literal: ^{ ... };
// 2. block declaration: return_t (^name) (int arg1, int arg2, ...) NB: return_t is optional and name is also optional
// 3. block inline call ^ return_t (int arg) { ... }; NB: return_t is optional
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