Methods to enumerate over paragraph ranges in a string using a block.

NSString+EnumerateParagraphs.h

//
//  NSString+EnumerateParagraphs.h
//  Ingist
//
//  Created by Brent Royal-Gordon on 7/19/13.
//  Copyright (c) 2013 Architechies. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface NSString (EnumerateParagraphs)

- (void)enumerateParagraphsContainingRange:(NSRange)range usingBlock:(void(^)(NSRange paraRange, BOOL * stop))block;
- (void)enumerateParagraphsInRange:(NSRange)range usingBlock:(void(^)(NSRange paraRange, BOOL * stop))block;

@end

NSString+EnumerateParagraphs.m

//
//  NSString+EnumerateParagraphs.m
//  Ingist
//
//  Created by Brent Royal-Gordon on 7/19/13.
//  Copyright (c) 2013 Architechies. All rights reserved.
//

#import "NSString+EnumerateParagraphs.h"

@implementation NSString (EnumerateParagraphs)

- (void)enumerateParagraphsContainingRange:(NSRange)range usingBlock:(void(^)(NSRange paraRange, BOOL * stop))block {
    range = [self paragraphRangeForRange:range];
    [self enumerateParagraphsInRange:range usingBlock:block];
}

- (void)enumerateParagraphsInRange:(NSRange)range usingBlock:(void (^)(NSRange, BOOL *))block {
    NSUInteger start = range.location;
    BOOL stop = NO;
    
    while(!stop && start != NSMaxRange(range)) {
        NSUInteger end;
        [self getParagraphStart:NULL end:&end contentsEnd:NULL forRange:NSMakeRange(start, 0)];
        
        NSRange range = NSMakeRange(start, end - start);
        block(range, &stop);
        
        start = end;
    };
}

@end