找到@ mentions的正则表达式函数不再起作用

Question

Xcode 8.3.3

我写了一个正则表达式方法来获取字符串的所有提及。

func getMentions() -> [String] {
    let pattern = "\\B@[A-Za-z0-9]+"
    do {
        let regex = try NSRegularExpression(pattern: pattern, options: NSRegularExpression.Options(rawValue: 0))
        let nsstr = self as NSString
        let all = NSRange(location: 0, length: nsstr.length)
        var matches : [String] = [String]()
        regex.enumerateMatches(in: self, options: NSRegularExpression.MatchingOptions(rawValue: 0), range: all) {
            (result : NSTextCheckingResult?, _, _) in
            if let r = result {
                let result = nsstr.substring(with: r.range) as String
                matches.append(result)
            }
        }
        Log.info(matches)
        return matches
    } catch {
        return []
    }
}

这曾经很好用。 但是，当我运行它时，我得到空的匹配。刚才有些事情得到了更新吗？

我也试过这个：

let pattern = "\\B@[A-Za-z0-9]+\\b"