using System;

using System.Collections.Generic;

using System.Text.RegularExpressions;

public class Program

{

    static string example = 

    "{"+

        "\"stringProp\":\"this is a string, with a comma\","+

        "\"objectProp\":{\"howdy\":\"there\"},"+

        "\"boolProp\":true,"+

        "\"intProp\":1,"+

        "\"floatProp\":1.5"+

    "}";

    public static void Main()

    {

        var regex = new Regex("[{,][\\s\\n]*\"([\\w\\s]+)\"\\s*:\\s*(?:\"([^\"]*)|({[^}]*})|([^,\\n}]*))");

​

        var dict = new Dictionary<string, string>();

        foreach (Match result in regex.Matches(example))

        {

            dict.Add(result.Groups[1].Value, $"{result.Groups[2].Value}{result.Groups[3].Value}{result.Groups[4].Value}");

        }

​

        Console.WriteLine($"stringProp: {GetString("stringProp")}");

        Console.WriteLine($"objectProp: {GetObject<string>("objectProp")}");

        Console.WriteLine($"boolProp: {GetBool("boolProp")}");

        Console.WriteLine($"intProp: {GetInt("intProp")}");

        Console.WriteLine($"floatProp: {GetFloat("floatProp")}");

        string GetString(string key) => dict[key];      

        bool GetBool(string key) => dict[key] == "true";        

        int GetInt(string key) => int.Parse(dict[key]);

        float GetFloat(string key) => float.Parse(dict[key]);

        string GetObject<T>(string key) { /*JSONUtility.FromJSON<T>(dict[key]);*/ return dict[key];}

    }

}