Using Optional.Some() to condense two guard statements into one.

condensed-pure.swift

var phone: String? {

    guard
        let phone = phoneNumberTextField?.text,
        let phoneDetector = try? NSDataDetector(types: NSTextCheckingType.PhoneNumber.rawValue),
        let range = pure(NSRange(location: 0, length: phone.startIndex.distanceTo(phone.endIndex))),
        let matches = pure(phoneDetector.matchesInString(phone, options: [], range: range))
        where matches.count > 0
    else {
        return nil
    }
    
    return phone
}

func pure<T>(a: T) -> T? {
	return .Some(a)
}

condensed.swift

var phone: String? {

    guard
        let phone = phoneNumberTextField?.text,
        let phoneDetector = try? NSDataDetector(types: NSTextCheckingType.PhoneNumber.rawValue),
        let range = Optional.Some(NSRange(location: 0, length: phone.startIndex.distanceTo(phone.endIndex))),
        let matches = Optional.Some(phoneDetector.matchesInString(phone, options: [], range: range))
        where matches.count > 0
    else {
        return nil
    }
    
    return phone
}

separate.swift

var phone: String? {

    guard
        let phone = phoneNumberTextField?.text,
        let phoneDetector = try? NSDataDetector(types: NSTextCheckingType.PhoneNumber.rawValue)
    else {
        return nil
    }

    let range = NSRange(location: 0, length: phone.startIndex.distanceTo(phone.endIndex))
    let matches = phoneDetector.matchesInString(phone, options: [], range: range)
    if matches.count == 0 {
        return nil
    }
    
    return phone
}