Is it possible to create a category of the “Block” object in Objective-C

Question

I would like to add functions by creating a category for Objective-C Blocks.

__block int (^aBlock)(int) = ^int( int n ){
    if( n <= 1 ) return n;
    return         


        

Answer 1

Dave DeLong is right, you cannot add a category on a class that you cannot see, but as blocks are subclasses of NSBlock adding:

@interface NSBlock : NSObject
@end

Now you can 'see' NSBlock and add a category on it, e.g.:

@interface NSBlock (map)
- (NSArray *)mapTo:(NSArray *)array;
@end

@implementation NSBlock (map)
- (NSArray *)mapTo:(NSArray *)array
{
    ...
}
@end

Still probably not the best thing to do in code that is actually used in production...