Swift in-expression verification mailbox

Write the following code within the playground, and the regular keyword is no different from other languages

Class Regex {Let    internalexpression:nsregularexpression let    pattern:string        init (pattern:string) {        Self.pattern = Pattern        var error:nserror?        Self.internalexpression = Nsregularexpression (Pattern:pattern, options:NSRegularExpressionOptions.CaseInsensitive , error: &error)!    }        Func Match (input:string), Bool {let        matches = self.internalExpression.matchesInString (input, Options:nil, Range:nsmakerange (0, count (input)))        return matches.count > 0    }}var email_regex = "^[a-za-z0-9]+ ([. _\\-]) *[a-za-z0-9]*@ ([a-za-z0-9]) + (. ( [A-za-z]) +) +$ "var regex = Regex (Pattern:email_regex) regex.match (" [email protected] ")  //return True
Regex.match ("[email protected]")//return true
Regex.match ("[email protected]")//return true

Swift in-expression verification mailbox