using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
public class Test
{
public static void Main()
{
var s = "{?:participants::lookup(.,{eeid},[[{catalog}]])}";
var rx = @"(?<!\[\[)\{([^:{}]*)}(?!]])";
var res = Regex.Matches(s, rx).Cast<Match>().Select(x => x.Groups[1].Value);
foreach (var t in res)
Console.WriteLine(t);
}
}
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