import Foundation
// WARNING: You included a flag that Swift doesn't support: J
// Wehn this flag is set, it allows duplicated capturing group names.
// By default, Swift captures only the last value matched for a repeated capture group.
// As an alternative, the pattern can be modified to contain one capturing group per group you want to get in the result.
let pattern = ##"""
(?<!\\) # Check it was not escaped with a \
(?<img_all>
\!\[(?<img_alt>.+?)\] # image alternative text, i.e. the text used when the image does not
(?:
(?:
[ ]? # possibly followed by some spaces
(?:\n[ ]*)? # and a new line with some space
\[(?<img_id>.*?)\] # with the link id in brackets, but may be empty
)
|
(?:
(?:
\(
[ \t]*
<(?<img_url> # link url within <>; or
.+?
)>
[ \t]* # possibly followed by some spaces or tabs
(?:
(?<img_title_container>['"]) # Title is surrounded ether by double or single quotes
(?<img_title>.*?) # actual title, but could be empty as in ""
\g{img_title_container} # make the sure enclosing mark balance
)?
[ \t]*
\)
)
|
(?:
\(
[ \t]*
(?<img_url> # link url within <>; or
(?:((?!["']).)*+|.*)
)
[ \t]*
(?:
(?<img_title_container>['"]) # Title is surrounded ether by double or single quotes
(?<img_title>.*?) # actual title, but could be empty as in ""
\g{img_title_container} # make the sure enclosing mark balance
)?
[ \t]*
\)
)
)
)
[ \t]*
(?<!\\)
\{
[[:blank:]\h]*
(?<img_attr>.+?)
[[:blank:]\h]*
\}
)
"""##
let regex = try! NSRegularExpression(pattern: pattern, options: [.anchorsMatchLines, .allowCommentsAndWhitespace])
let testString = ##"""
This is an {.class #inline-img}.
.jpg'Title here') {.class #inline-img} and some text after
 {.class #inline-img}
"""##
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