とりあえず書き殴ってみたSwiftでの正規表現ユーティリティ。正しさとかパフォーマンスは保証しないよ。

Regex.swift

import Foundation

class Regex {
    let internalExpression: NSRegularExpression
    let pattern: String

    init(_ pattern: String) {
        self.pattern = pattern
        var error: NSError?
        self.internalExpression = NSRegularExpression(pattern: pattern, options: nil, error: &error)!
    }

    func matches(input: String) -> Bool {
        let matches = self.internalExpression.matchesInString(input, options: nil, range:NSMakeRange(0, countElements(input)))
        return matches.count > 0
    }
    
    func groups(input: String) -> [String]? {
        let matches = self.internalExpression.matchesInString(input, options: nil, range:NSMakeRange(0, countElements(input)))
        if matches.count > 0 {
            var result: [String] = []
            for i in 0 ..< matches.count {
                let nsrange: NSRange = (matches[i] as NSTextCheckingResult).range
                let nsstring: NSString = input as NSString
                let group: String = nsstring.substringWithRange(nsrange)
                result.append(group)
            }
            return result
        } else {
            return nil
        }
    }
}

String.swift

import Foundation

infix operator =~ { associativity left precedence 130 }
func =~ (input: String, pattern: String) -> Bool {
    return Regex(pattern).matches(input)
}