macOS Subscripts and NSStrings...

[ArtOfWarfare]

Threw these categories together and felt like sharing:

@implementation NSString (subscript)

- (id)objectAtIndexedSubscript:(NSUInteger)index {
    return @([self characterAtIndex:index]);
}

- (id)objectForKeyedSubscript:(id)key {
    return [NSValue valueWithRange:[self rangeOfString:key]];
}

@end

@implementation NSMutableString (subscript)

- (void)setObject:(id)obj atIndexedSubscript:(NSUInteger)idx {
    if ([obj isKindOfClass:NSNumber.class]) {
        unichar ch = [obj unsignedShortValue];
        obj = [NSString stringWithCharacters:&ch length:1];
    }
    [self replaceCharactersInRange:NSMakeRange(idx, 1) withString:obj];
}

- (void)setObject:(id)obj atKeyedSubscript:(id)key {
    [self replaceOccurrencesOfString:key withString:obj options:0 range:NSMakeRange(0, self.length)];
}

@end

Alternatively, maybe objectAtIndexedSubscript: should return a single character long NSString...