import Foundation
let pattern = ######"""
(?(DEFINE) # start DEFINE block
# pre-define quant subroutine
(?<quant>many|some|five)
# pre-define adj subroutine
(?<adj>blue|large|interesting)
# pre-define object subroutine
(?<object>cars|elephants|problems)
# pre-define noun_phrase subroutine
(?<noun_phrase>(?&quant)\ (?&adj)\ (?&object))
# pre-define verb subroutine
(?<verb>borrow|solve|ressemble)
) # end DEFINE block
##### The regex matching starts here #####
(?&noun_phrase)\ (?&verb)\ (?&noun_phrase)
"""######
let regex = try! NSRegularExpression(pattern: pattern, options: .allowCommentsAndWhitespace)
let testString = #"""
five blue elephants solve many interesting problems
many large problems ressemble some interesting cars
"""#
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let matches = regex.matches(in: testString, range: stringRange)
var result: [[String]] = []
for match in matches {
var groups: [String] = []
for rangeIndex in 1 ..< match.numberOfRanges {
let nsRange = match.range(at: rangeIndex)
guard !NSEqualRanges(nsRange, NSMakeRange(NSNotFound, 0)) else { continue }
let string = (testString as NSString).substring(with: nsRange)
groups.append(string)
}
if !groups.isEmpty {
result.append(groups)
}
}
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