gistfile1.m

#import <Foundation/Foundation.h>

@implementation NSArray (BlocksTest)

- (void) do:(void (^)(id))aBlock;
{
	[self enumerateObjectsUsingBlock:
		^(id obj, NSUInteger idx, BOOL *stop) {
			aBlock(obj);
		}];
}


- (id) inject:(id)aValue into:(id (^)(id, id))aBlock;
{
	__block id sum = aValue;
	[self do:^(id each){
		sum = aBlock(sum, each);
	}];
	return sum;
}

@end



int main (int argc, const char * argv[]) {
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
	
	id array = [NSArray arrayWithObjects:@"first", @"second", @"third", nil];
//	[array do:^(id each){
//		NSLog(@"%@", each);
//	}];
//	
	// crashes, why?
	NSLog(@"%@", [array inject:@"" into:(id) ^(id concatenation, id element){
		return [concatenation stringByAppendingString:element];
//		return [concatenation stringByAppendingFormat:@", %@", element];
	}]);
		
	[pool drain];
    return 0;
}