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Injection in Objective-C
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// Enumerable.h | |
#import <Foundation/Foundation.h> | |
typedef id (^InjectBlock)(id, id); | |
@interface NSArray (Enumerable) | |
- (id) inject:(id) initial block:(InjectBlock) block; | |
@end | |
// Enumerable.m | |
#import "Enumerable.h" | |
@implementation NSArray (Enumerable) | |
- (id) inject:(id) initial block:(InjectBlock) block { | |
id memo = initial; | |
if (!memo) | |
memo = [self objectAtIndex: 0]; | |
for (id obj in self) { | |
memo = block(memo, obj); | |
} | |
return memo; | |
} | |
@end | |
// main.m | |
#import "Enumerable.h" | |
int main(int argc, char *argv[]) { | |
NSArray *ary = [NSArray arrayWithObjects: @"cat", @"sheep", @"bear", nil]; | |
InjectBlock block = ^ id (id memo, id word) { | |
return ((NSString *)memo).length > ((NSString *)word).length ? memo : word; | |
}; | |
id longestWord = [ary inject: nil block: block]; | |
NSLog(@"Longest word %@", longestWord); | |
} |
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