Swift regular expressions

Another little something to copy and paste into a Swift Playground... Regular expression matching in Swift with a couple of little helper functions. Obviously the mapping to Objective C is key here. Otherwise it's pretty much business as usual. 

import Foundation

func matches(searchString:String, pattern : String)->Bool{
  var error:NSError?
  let regex = NSRegularExpression .regularExpressionWithPattern(pattern, options: NSRegularExpressionOptions.DotMatchesLineSeparators, error: &error)
    
  if (!error){
      let matchCount = regex.numberOfMatchesInString(searchString, options: NSMatchingOptions.fromMask(0), range: NSMakeRange(0, countElements(searchString)))
        
      return matchCount > 0
  }
  return false
}
        
func replace(searchString:String, pattern : String, replacementPattern:String)->String?{
  var error:NSError?
  let regex = NSRegularExpression .regularExpressionWithPattern(pattern, options: NSRegularExpressionOptions.DotMatchesLineSeparators, error: &error)
  if (!error){
     let replacedString = regex.stringByReplacingMatchesInString(searchString, options: NSMatchingOptions.fromMask(0), range: NSMakeRange(0, countElements(searchString)), withTemplate: replacementPattern)
     return replacedString
  }
  return nil
}

matches("Hello, Swift", "Swift")
println(replace("Hello Objective-C","Objective-C","Swift, Goodbye $0"))