using System;
using System.Text;
using System.Text.RegularExpressions;
using System.Collections.Generic;

public class Test
{
	
public static string Format(string formatWithNames, IDictionary<string, object> data) {
	int pos = 0;
    var args = new List<object>();
	var fmt = Regex.Replace(
		formatWithNames
	,   @"(?<={)[^}]+(?=})"
	,   new MatchEvaluator(m => {
            var res = (pos++).ToString();
            var tok = m.Groups[0].Value.Split(':');
            args.Add(data[tok[0]]);
            return tok.Length == 2 ? res+":"+tok[1] : res;
        })
	);
    return string.Format(fmt, args.ToArray());
}
	
	public static void Main()
	{


var x = new Dictionary<string,object> {
    {"brown", 123}
,   {"jumps", 21}
,   {"lazy", 42}
};
Console.WriteLine("{0}", Format("Quick {brown} fox {jumps:C} over the {lazy:P} dog", x));

	}
}