Define a Regex Expression in C# to parse TCL syntax, allowing multiple strings in the token stream including “”, “\””, and “\{“. TCL is very string

Try this. It handles any escaped quotes inside quotes.

@"(?:(""[^\\""]*(?:\\.[^\\""]*)*"")|([\[\]{}();,])|([%*+\-/])|(<<|>>)|([!=]=|[<>]=?)|(!|&&|\|\|)|([&\^|])|([:?])|\s+)"

regex101.com/r/ad0038/1

{
   //for example  
   string line1 = @"[return [file attributes $var -readonly]";
   string line2 = @"set x[string map { ""\"""" """"} $var]";
   
   //The original regex is   
   //string in ""| certain chars| whitespace | all the operators
   string pattern = @"(?:(""[^\\""]*(?:\\.[^\\""]*)*"")|([\[\]{}();,])|([%*+\-/])|(<<|>>)|([!=]=|[<>]=?)|(!|&&|\|\|)|([&\^|])|([:?])|\s+)";
   
   //does the tokenizing  
   string[] regexResult = Regex.Split(line2, pattern, RegexOptions.None);
   
   int cnt = 0;
   int arysize = regexResult.Length;
   foreach (String str in regexResult)
   {
       if (str != "")
       {
           Console.Write(str);
           if (cnt < arysize - 2)
               Console.Write(", ");
       }
       cnt++;
   }
   Console.WriteLine();
}

Output:

set, x, [, string, map, {, "\"", "", }, $var, ]

Refactored:

(?:
   
   (                             # (1 start)
      "
      [^\\"]* 
      (?: \\ . [^\\"]* )*
      " 
   )                             # (1 end)
 | ( [\[\]{}();,] )              # (2)
 | ( [%*+\-/] )                  # (3)
 | ( << | >> )                   # (4)
 | ( [!=] = | [<>] =? )          # (5)
 | ( ! | && | \| \| )            # (6)
 | ( [&\^|] )                    # (7)
 | ( [:?] )                      # (8)
 | \s+    
)