JSFeedParser(parser:foundCData:).m

/* NOTES:
   Fun use of a higher-order-block and some maybe objects.
 */

- (void)parser:(NSXMLParser *)parser foundCDATA:(NSData *)CDATABlock {
  Function (^blockForEncoding)(NSStringEncoding) = ^Function (NSStringEncoding enc) {
    return [^(id d) { return [[[NSString alloc] initWithData:d encoding:enc] autorelease]; } copyrelease];
  };
  
  id utf8Str = [[FKMaybe return:CDATABlock] map:blockForEncoding(NSUTF8StringEncoding)];
  id latin1Str = [[FKMaybe return:CDATABlock] map:blockForEncoding(NSISOLatin1StringEncoding)];
  
  [[utf8Str orElse:latin1Str] foreach:^(id str) {
    [self.currentText appendString:str];
    NSLog(@"result: %@", str);
  }];
}

JSFeedParser(startConnection).m

/* NOTES:
   -[JSFeedParser startConnection] starts the chain of events that results in a feed
   being downloaded and parsed. But if the connection cannot be made in the very
   beginning, it's useful to know about that's why I've tried to wrap as many
   of my action methods in JSFeedParser in FKEither. That way, I can NSLog
   the return value of any message and see if it failed or succeeded. In fact, if
   these methods are invoked from within each other (a perfect tree of invocations)
   the return value of the last method to be called will be either its Right value
   or the value of the first error to occur in the chain. Hence, you can linearly
   fix bugs in your pipeline. How cool is that?
 */

- (FKEither *)startConnection {
  [self reset];
  
  NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] initWithURL:self.feedURL
                                                               cachePolicy:NSURLRequestReloadIgnoringLocalAndRemoteCacheData
                                                           timeoutInterval:180] autorelease];
  [request setValue:NSStringFromClass([self class]) forHTTPHeaderField:@"User-Agent"];
  
  self.connection = [[[NSURLConnection alloc] initWithRequest:request delegate:self] autorelease];
  
  return [[[FKEither return:self] bind:^(id s) {
    id err = [NSString stringWithFormat:@"Asynchronous connection failed to URL %@",
              self.feedURL.absoluteString];
    return [FKEither right:self.connection orLeft:err];
  }] foreach:^(id c) {
    self.asynchronousData = [[NSMutableData new] autorelease];
  }];
}