Convert subscript function from Objective C to Swift - objective-c

Question

I am trying to convert some Objective C code to Swift and can't manage to do it right with subscripting.
This is the method I am trying to migrate to Swift:
- (NSArray *)rangesOfSubstringAlphaNumeric:(NSString *)substring rangesLimit:(NSUInteger)rangesLimit {
NSAssert(rangesLimit, #"A range limit grather than 0 must be specified");
if (!substring.length) {
return nil;
}
static NSCharacterSet * restrictedCharacters = nil;
if (!restrictedCharacters) {
restrictedCharacters = [[NSCharacterSet alphanumericCharacterSet] invertedSet];
}
NSArray * substrings = [substring componentsSeparatedByCharactersInSet:restrictedCharacters];
NSMutableArray * allRanges = [NSMutableArray array];
NSString *searchedString = self;
for (NSString *stringToMatch in substrings) {
if (![stringToMatch isEqualToString:#""]) {
NSRange aRange;
NSUInteger lastLocation = 0;
NSUInteger foundRanges = 0;
while (foundRanges++ < rangesLimit &&
(aRange = [searchedString localizedStandardRangeOfString:stringToMatch]).location != NSNotFound) {
searchedString = [searchedString substringFromIndex:aRange.location + aRange.length];
aRange.location = aRange.location + lastLocation;
lastLocation = aRange.location + aRange.length;
[allRanges addObject:[NSValue valueWithRange:aRange]];
}
}
}
return allRanges.count ? [allRanges copy] : nil;
}
I got stuck on the subscripting part since it seems I cannot assign integer values to Indexes and conversion from Index to Int is out of hand for me I'm kind of stuck, this is what I managed to do:
func rangesOfAlphanumeric(substring: String, limit: UInt) -> [Range<String.Index>] {
guard limit > 0, !substring.isEmpty else {
if limit == 0 {
assert(false, "limit must be greather than 0")
}
return []
}
var searchedString = self
let substrings = substring.components(separatedBy: NSCharacterSet.restricted)
for stringToMatch in substrings {
if !stringToMatch.isEmpty {
// var aRange: Range<String.Index>?
// var lastLocation: UInt = 0
// var foundRanges: UInt = 0
// while foundRanges < limit,
// let tempRange = searchedString.localizedStandardRange(of: stringToMatch),
// !tempRange.isEmpty {
//
// searchedString = String(searchedString[tempRange.upperBound...])
// if let lastLocation = lastLocation {
// aRange = temp
// }
// }
}
}
}
UPDATE: Solution below.

Answer 1

Managed to resolve the issue using the ranges function posted here:
func rangesOfAlphanumeric(substring: String) -> [Range<String.Index>] {
var searchedString = self
let substrings = substring.components(separatedBy: NSCharacterSet.restricted)
return substrings.compactMap { (stringToMatch) -> [Range<String.Index>]? in
guard !stringToMatch.isEmpty else {
return nil
}
let ranges = searchedString.ranges(of: stringToMatch, options: [
.diacriticInsensitive,
.caseInsensitive
])
if let lastRange = ranges.last {
searchedString = String(searchedString[index(after: lastRange.upperBound)])
}
return ranges
}.flatMap{$0}
}

Answer 2

I created this repo with swift 5 is very easy to use
all is already set up. you have just to change the IAP ids
The Github repo