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Creating a regular expression object from a String literal
class Regex {
let pattern: String
let options: NSRegularExpressionOptions!
private var matcher: NSRegularExpression {
return NSRegularExpression(pattern: self.pattern, options: nil, error: nil)
required init(pattern: String, options: NSRegularExpressionOptions = nil) {
self.pattern = pattern
self.options = options
func match(string: String, options: NSMatchingOptions = nil) -> Bool {
return self.matcher.numberOfMatchesInString(string, options: options, range: NSMakeRange(0, string.utf16Count)) != 0
extension Regex: StringLiteralConvertible, ExtendedGraphemeClusterLiteralConvertible {
typealias ExtendedGraphemeClusterLiteralType = StringLiteralType
class func convertFromExtendedGraphemeClusterLiteral(value: ExtendedGraphemeClusterLiteralType) -> Self {
return self(pattern: value)
class func convertFromStringLiteral(value: StringLiteralType) -> Self {
return self(pattern: value)
// MARK: -
protocol RegularExpressionMatchable {
func match(regex: Regex) -> Bool
infix operator =~ { associativity left precedence 130 }
func =~<T: RegularExpressionMatchable> (left: T, right: Regex) -> Bool {
return left.match(right)
extension String: RegularExpressionMatchable {
func match(regex: Regex) -> Bool {
return regex.match(self)
"foo" =~ "f" // true
winzig commented Aug 12, 2014

Awesome! Why isn't this part of Swift? ;-)

neilpa commented Aug 12, 2014

I'm assuming you intended to pass self.options to the NSRegularExpression c'tor when creating the matcher.

Thank you! Great! Your code was working in my project until i (to bad) updated to Xcode 6.1, now i am getting 3 errors in extension Regex: Type 'Regex' does not confirm to protocol 'StringLiteralConvertible'; to protocol 'Unicode ScalarLiteralConvertible'; to protocol 'ExtendedGraphemeClusterLiteralConvertible'.

grosch commented Nov 26, 2014

I've taken this and updated it for the current version of Xcode, and also made it so you can use an actual NSRegularExpression as the RHS. See

ded commented Jun 30, 2015

thank you for this!

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