How To Use the CHCSVParser class

I tried using this today, based on @DaveDeLong's excellent answer and code, but I think the software has been revised since his (2010) answer. At the time of writing, I found I had to use this:

@interface CSVParserDelegate : NSObject <CHCSVParserDelegate> {
  NSMutableArray * currentRow;
}
@end

@implementation CSVParserDelegate

- (void) parser:(CHCSVParser *)parser didBeginLine:(NSUInteger)lineNumber {
  currentRow = [[NSMutableArray alloc] init];
}
- (void) parser:(CHCSVParser *)parser didReadField:(NSString *)field atIndex:(NSInteger)fieldIndex {
  [currentRow addObject:field];
}
- (void) parser:(CHCSVParser *)parser didEndLine:(NSUInteger)lineNumber {
  NSLog(@"finished line! %@", currentRow);
  [self doSomethingWithLine:currentRow];
  [currentRow release], currentRow = nil;
}
@end

i.e., parser:didStartLine:lineNumber: has become parser:didBeginLine:lineNumber: and parser:didReadField: has become parser:didReadField:atIndex:.

I'm glad to see that my code is proving useful! :)

CHCSVParser is similar in behavior to an NSXMLParser, in that every time it finds something interesting, it's going to let you know via one of the delegate callbacks. However, if you choose to ignore the data that it gives you in the callback, then it's gone. These parsers (CHCSVParser and NSXMLParser) are pretty stupid. They just know the format of the stuff they're trying to parse, but don't really do much beyond that.

So the answer, in a nutshell, is "you have to save it yourself". If you look at the code for the NSArray category, you'll see in the .m file that it's using a simple NSObject subclass as the parser delegate, and that subclass is what's aggregating the fields into an array, and then adding that array to the overall array. You'll need to do something similar.

Example delegate:

@interface CSVParserDelegate : NSObject <CHCSVParserDelegate> {
  NSMutableArray * currentRow;
}
@end

@implementation CSVParserDelegate

- (void) parser:(CHCSVParser *)parser didStartLine:(NSUInteger)lineNumber {
  currentRow = [[NSMutableArray alloc] init];
}
- (void) parser:(CHCSVParser *)parser didReadField:(NSString *)field {
  [currentRow addObject:field];
}
- (void) parser:(CHCSVParser *)parser didEndLine:(NSUInteger)lineNumber {
  NSLog(@"finished line! %@", currentRow);
  [self doSomethingWithLine:currentRow];
  [currentRow release], currentRow = nil;
}
@end

However, I could be convinced to modify the behavior of the parser to aggregate the row itself, but if I go down that route, why not just have the parser aggregate the entire file? (Answer: it shouldn't)

To use CHCSVParser with Swift you can use a swift wrapper for basic needs