gistfile1.txt

dispatch_block_t RecursiveBlock(void (^block)(dispatch_block_t recurse))
{
    // assuming ARC, so no explicit copy
    return ^{ block(RecursiveBlock(block)); };
}

typedef void (^OneParameterBlock)(id parameter);

OneParameterBlock RecursiveBlock1(void (^block)(OneParameterBlock recurse, id parameter))
{
    return ^{ block(RecursiveBlock1(block), parameter) };
}

use:

dispatch_block_t block = RecursiveBlock(^(dispatch_block_t recurse) {
    if(!done)
        recurse();
    else
        ...
});

block();