private void RenameIdentifiers MatchCollection matches Regex Matches c

private void RenameIdentifiers()
{
    MatchCollection matches = Regex.Matches(code, @"(var|function) (\w+)");
    foreach (Match match in matches)
    {
        Console.WriteLine(match.Value);
        string oldName = match.Groups[2].Value;
        string newName = namesManager.NextName;

        string pattern = @"(\W)" + oldName + @"(\W)";
        string replacement = "$1" + newName + "$2";
        code = Regex.Replace(code, pattern, replacement);
    }
}