import Foundation
let pattern = #"(?:<datasource>[^/]*?|.*(?=<datasource>)|(?=</datasource>).*)(*SKIP)(*FAIL)|/"#
let regex = try! NSRegularExpression(pattern: pattern, options: .dotMatchesLineSeparators)
let testString = #"""
<id>SomeID</id>
<datasource>C:/projects/my_project/my_file.jpg</datasource>
<title>My title can include / and other characters</title>
<abstract></abstract>
"""#
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let substitutionString = #"\\"#
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