you also need LitJson.dll

TraceryDecoder.cs

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


public class TraceryDecoder : MonoBehaviour {

	public string tracery;

	public bool bangDecode;
	public bool bangGenerate;

	// Use this for initialization
	void Start () {
	
	}
	
	// Update is called once per frame
	void Update () {
		if (bangDecode)
		{
			bangDecode = false;
			Decode();
		}
		if (bangGenerate)
		{
			bangGenerate = false;
			var ret = Generate(Decode());
			Debug.Log(ret);
		}
	}

	Regex rgx = new Regex(@"\#(?<expand>[^\#]*?)\#", RegexOptions.IgnoreCase);

	public string Generate(Dictionary<string,string[]> parsed)
	{
		return Expand("origin", parsed);
	}

	public string Expand(string token, Dictionary<string,string[]> parsed)
	{
		if (parsed.ContainsKey(token))
		{
			
			var ret = parsed[token].PickRandom();
			return rgx.Replace(ret, m => Expand(m.Groups[1].Value, parsed));
		}
		else
		{
			return "[" + token + "]";
		}
	}




	Dictionary<string,string[]> Decode()
	{
		Dictionary<string,string[]> traceryStruct = new Dictionary<string, string[]>();
		var map = JsonToMapper(tracery);
		foreach (var key in map.Keys) {

			string[] entries = new string[map[key].Count];
			for (int i = 0; i < map[key].Count; i++) {
				var entry = map[key][i];
				entries[i] = (string)entry;
			}
			traceryStruct.Add(key, entries);
		}
		return traceryStruct;
	}
	public static JsonData JsonToMapper(string tracery)
	{
		var traceryStructure = JsonMapper.ToObject(tracery);
		return traceryStructure;

    }
}