import Foundation
let pattern = #"""
(?s)
<page>
(
.*?
(?:
(?: <page> | </page> )
(*SKIP) (*FAIL)
| {{Infobox
)
.*?
)
(?: <page> (*SKIP) (*FAIL) | </page> )
"""#
let regex = try! NSRegularExpression(pattern: pattern, options: .allowCommentsAndWhitespace)
let testString = #"""
List of keywords :
keyword1 = <page>
keyword2 = </page>
keyword3 = {{Infobox
Example A:
<page>
text to consider without {{ not-Infobox
</page>
Result => do not extract (or keep or split) this part.
Example B:
<page>
text to consider with {{Infobox here}}
</page>
Result => extract (or keep or split) this part.
"""#
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let substitutionString = #"$1"#
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