let inputText: String = <some text to match against>

// Build the regex to match against (in this case, <number>\t<string>)
// This regex has two capture groups, one for the number and one for the string.
let regex = try DSFRegex(#"(\d*)\t\"([^\"]+)\""#)

// Retrieve ALL the matches for the supplied text
let searchResult = regex.matches(for: inputText)

// Loop over each of the matches found, and print them out
searchResult.forEach { match in 
   let foundStr = inputText[match.range]          // The text of the entire match
   let numberVal = inputText[match.captures[0]]   // Retrieve the first capture group text.
   let stringVal = inputText[match.captures[1]]   // Retrieve the second capture group text.

   Swift.print("Number is \(numberVal), String is \(stringVal)")
}

// Match against dummy phone numbers XXXX-YYY-ZZZ
let phoneNumberRegex = try DSFRegex(#"(\d{4})-(\d{3})-(\d{3})"#)

let hasAMatch = phoneNumberRegex.hasMatch("0499-999-999")   // true
let noMatch = phoneNumberRegex.hasMatch("0499 999 999")     // false

let result = phoneNumberRegex.matches(for: "0499-999-999 0491-111-444 4324-222-123")
result.forEach { match in 
   let matchText = result.text(for: match.element)
   Swift.print("Match `\(matchText)`")
   for capture in match.captures {
      let captureText = result.text(for: capture)
      Swift.print(" - `\(captureText)`")
   }
}

/// Find all email addresses within a text
let inputString = "… some input string …"
let emailRegex = try DSFRegex("… some regex …")
emailRegex.enumerateMatches(in: inputString) { (match) -> Bool in

   // Extract match information
   let matchRange = match.range
   let matchText = inputString[match.range]
   Swift.print("Found '\(matchText)' at range \(matchRange)")
   
   // Continue processing
   return true
}

var searchCursor: DSFRegex.Cursor?
var content: String

@IBAction func startSearch(_ sender: Any) {
   let regex = DSFRegex(... some pattern ...)
   
   // Find the first match in the string
   self.searchCursor = self.content.firstMatch(for: regex)
   
   self.displayForCurrentSearch()
}

@IBAction func nextSearchResult(_ sender: Any) {
   if let previous = self.searchCursor {
   	   // Find the next match in the string from the 
      self.searchCursor = self.content.nextMatch(for: previous)
   }
   self.displayForCurrentSearch()
}

internal func displayForCurrentSearch() {
   // Update the UI reflecting the search result found in self.searchCursor
   ...
}

// Redact email addresses within the text
let emailRegex = try DSFRegex("… some regex …")
let redacted = emailRegex.stringByReplacingMatches(
    in: inputString,
    withTemplate: NSRegularExpression.escapedTemplate(for: "<REDACTED-EMAIL-ADDRESS>")
)

let phoneNumberRegex = try DSFRegex(#"(\d{4})-(\d{3})-(\d{3})"#)
let results = phoneNumberRegex.matches(for: "4499-999-999 3491-111-444 4324-222-123")

// results.numberOfMatches == 3
// results.text(match: 0) == "4499-999-999"
// results.text(match: 1) == "3491-111-444"
// results.text(match: 2) == "4324-222-123"

// Just retrieve the text for each of the matches
let textMatches = results.textMatching()  // == ["4499-999-999", "3491-111-444, "4324-222-123"]

let first = phoneNumberRegex.firstMatch(in: "4499-999-999 3491-111-444 4324-222-123")

let allMatches = phoneNumberRegex.matches(for: "0499-999-999 0491-111-444 4324-222-123")
for match in allMatches.matches.enumerated() {
   let matchText = allMatches.text(for: match.element)
   Swift.print("Match (\(match.offset)) -> `\(matchText)`")
   for capture in match.element.capture.enumerated() {
      let captureText = allMatches.text(for: capture.element)
      Swift.print("  Capture (\(capture.offset)) -> `\(captureText)`")
   }
}

/// Find all email addresses within a text
let emailRegex = try DSFRegex("… some regex …")
let inputString = "This is a test.\n [email protected] and [email protected], [email protected] lives here"

var count = 0
emailRegex.enumerateMatches(in: inputString) { (match) -> Bool in
   
   count += 1

   // Extract match information
   let matchRange = match.range
   let nsRange = NSRange(matchRange, in: inputString)
   let matchText = inputString[match.range]
   Swift.print("\(count) - Found '\(matchText)' at range \(nsRange)")

   // Stop processing if we've found more than two
   return count < 2
}