Swift String extension to ease working with regular expressions

String+RegularExpression.swift

//
//  String+RegularExpression.swift
//
//  Created by Alexander Ney on 15/06/2014.
//  Copyright (c) 2014 Alexander Ney. All rights reserved.
//

import Foundation


// Compate String related Ranges
@infix func == (left: Range<String.Index>, right: Range<String.Index>) -> Bool
{
    return (left.startIndex == right.startIndex) && (left.endIndex == right.endIndex)
}

extension String
{
    
    // Full range of the string
    var range : Range<String.Index>
    {
        return Range(start: self.startIndex, end:self.endIndex)
    }
    
    // Returns ture if string matches the reuglar expression
    func matchesPattern(pattern: String) -> Bool
    {
        return self.rangeOfString(pattern, options: NSStringCompareOptions.RegularExpressionSearch) == self.range
    }
    
    // Returns an Array of tuples (range, matched string)
    func substringsMatchingPattern(pattern: String) -> Array<(Range<String.Index>,String)>
    {
        var matchingSubStrings : Array<(Range<String.Index>,String)> = []
        var range : Range<String.Index>
        var searchRange = self.range
        do {
            range = self.rangeOfString(pattern, options: .RegularExpressionSearch, range: searchRange)
            if !range.isEmpty
            {
                matchingSubStrings += (range, self.substringWithRange(range))
            }
            searchRange.startIndex = range.endIndex
        } while !range.isEmpty
        
        return matchingSubStrings
    }
}

get all substrings matching ${ ... } of a string and enumerate them:

for (_, substring) in sourceString.substringsMatchingPattern("\\$\\{.+?\\}")
{
    println(substring)
}