recursive trim

gistfile1.m

#import "NSAttributedString+DXYTrim.h"

@implementation NSAttributedString (DXYTrim)

- (NSAttributedString *)attrStringByTrimmingCharacterInSet:(NSCharacterSet *)set {
    __block __weak NSAttributedString*(^weak_leadingTrim)(NSAttributedString*);
    NSAttributedString*(^leadingTrim)(NSAttributedString*);
    weak_leadingTrim = leadingTrim = ^NSAttributedString*(NSAttributedString *attrString) {
        NSRange range = [attrString.string rangeOfCharacterFromSet:set];
        if (range.location == 0) {
            return weak_leadingTrim([attrString attributedSubstringFromRange:NSMakeRange(1, attrString.length-1)]);
        } else {
            return attrString;
        }
    };
    __block __weak NSAttributedString*(^weak_trailingTrim)(NSAttributedString*);
    NSAttributedString*(^trailingTrim)(NSAttributedString*);
    weak_trailingTrim = trailingTrim = ^NSAttributedString*(NSAttributedString *attrString) {
        NSRange range = [attrString.string rangeOfCharacterFromSet:set options:NSBackwardsSearch];
        if (range.location == attrString.length-1) {
            return weak_trailingTrim([attrString attributedSubstringFromRange:NSMakeRange(0, attrString.length-1)]);
        } else {
            return attrString;
        }
    };
    
    NSAttributedString *tmp = leadingTrim(self);
    tmp  = trailingTrim(tmp);
    return tmp;
}

@end