Question

I’m trying to convert a proprietary string mask to the .net equivalent of it. For that I need to exchange every occurance of [someText] with {aDigit}.

private static int hits = 0; private static object hitsLock = new object();  public static string ConvertSdsFileMaskToStringMask(string sdsFileMaskString) {     Regex bracketsExpression = new Regex(@'\[[^[]*]');     lock (hitsLock)     {         hits = 0;         return bracketsExpression.Replace(sdsFileMaskString, ReplaceSquareWithAngularBrackets);     } } private static string ReplaceSquareWithAngularBrackets(Match m) {     string result = String.Format('{{{0}}}', hits.ToString());     hits++;     return result; } 

It works. But both expressions need to know each other’s workings and are depending on the hits counter. I feel this could be improved. Ideally both have no dependency on each other. Any suggestions? This can probably be done better. Any suggestions?

Answer 1

Yes – use an anonymous method or lambda expression:

public static string ConvertSdsFileMaskToStringMask(string sdsFileMaskString)  {     Regex bracketsExpression = new Regex(@'\[[^[]*]');     int hits = 0;     return bracketsExpression.Replace(sdsFileMaskString, match =>      {         string result = String.Format('{{{0}}}', hits.ToString());         hits++;         return result;         }); } 

This will capture the local variable in a new (compiler-generated) type, getting rid of the ‘globalness’.

If you’re happy with side-effects, you could make the lambda expression simpler, too. I’d also get rid of the call to String.Format in this case, as all those braces are confusing:

public static string ConvertSdsFileMaskToStringMask(string sdsFileMaskString)  {     Regex bracketsExpression = new Regex(@'\[[^[]*]');     int hits = 0;     return bracketsExpression.Replace(sdsFileMaskString,          match => '{' + (hits++) + '}'); }