import Foundation
let pattern = #"(?s)\b(\w+)\b(?=.*:\1=(\w+)\b)"#
let regex = try! NSRegularExpression(pattern: pattern, options: .dotMatchesLineSeparators)
let testString = #"""
blue cheese, a red nose.
Dictionary:blue=bleu:red=rouge:green=vert
"""#
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let substitutionString = #"\2"#
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