import Foundation
// WARNING: You included a flag that Swift doesn't support: u
// When this flag is set, it makes the pattern and subject strings to be treated as unicode.
// Swift already treats the pattern and subject strings as unicode by default, so including this flag is redundant.
let pattern = #"(?=(?:(?:\\x1b\[[0-9;]+m)?.){80})(?:(?:\\x1b\[[0-9;]+m)?.){0,80}\K "#
let regex = try! NSRegularExpression(pattern: pattern)
let testString = #"Morbi leo risus, \x1b[34;1mporta ac consectetur\x1b[39;22m ac, vestibulum at eros. Aenean lacinia bibendum nulla sed consectetur. Nullam id dolor id nibh ultricies vehicula ut id elit. Aenean lacinia bibendum nulla sed consectetur. Curabitur blandit tempus porttitor."#
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let substitutionString = #"\n"#
let result = regex.stringByReplacingMatches(in: testString, range: stringRange, withTemplate: substitutionString)
print(result)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Swift 5.2, please visit: https://developer.apple.com/documentation/foundation/nsregularexpression