import Foundation
let pattern = #"""
(?(DEFINE)(?'nonbrace' [^{}\n] ))
(?(DEFINE)(?'begin' { ))
(?(DEFINE)(?'end' } ))
(?(DEFINE)(?'middle' (?&nonbrace) ))
(?(DEFINE)(?'nested'
((?&begin)((?&middle)|(?&nested))*(?&end))
))
^((?&nonbrace)*+(?&nested))*+(?&nonbrace)*$
"""#
let regex = try! NSRegularExpression(pattern: pattern, options: [.anchorsMatchLines, .allowCommentsAndWhitespace])
let testString = #"""
a
abc
{}
{a}
{{aa}}
{a{b}}
{a{bb}a}
{a{b{c}b}a}
n{a{}}nn{b{bb}}
\@writefile{toc}}}}{\contentsline {section}{\numberline {B
\@writefile{toc}{\contentsline {section}{\numberline {B
Previous lines contain mismatched braces. This and the next line don't.
\@writefile{toc}{\contentsline {section}{\numberline {B}}}
"""#
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