using System;
using System.IO;
using System.Text;
using System.Text.RegularExpressions;
public class Test
{
public static void Main()
{
var s = "\"foo\" {{\"bar\"}}";
var rx = new Regex(@"""(?=[^}]*(?:}})*[^}]*$)|(?<=^[^{]*(?:{{)*)""");
Console.WriteLine(string.Format("$@\"{0}\"",rx.Replace(s,"\"\"")));
}
}
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