import Foundation
let pattern = ##"\[color=(#[0-9A-F]{3,6})\](.*?)\[\/color\]"##
let regex = try! NSRegularExpression(pattern: pattern, options: .anchorsMatchLines)
let testString = ##"""
[color=red;font-size:100pt;]DEFACED[/color]
[color=#FF0000]DEFACED?[/color]
"""##
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let substitutionString = #"<span style="font-color:$1>$2</span>"#
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