Add save/load

[david-a-wheeler]

Add the ability to save/load games (stories) in progress.

[david-a-wheeler]

Save/load requires a place to store data, and a way to represent data that can be reloaded later. Let's deal with a place to store data first.

The easy way to store data is client-side. Storing data client-side can be done with cookies, but the amount of storage allowed is limited. More storage is available on clients via the Web storage API (use "local" not "session" mode); these are now widely supported. More info:
http://www.w3schools.com/html/html5_webstorage.asp
https://developer.mozilla.org/en-US/docs/Web/API/Web_Storage_API
http://www.w3.org/TR/webstorage/
http://html5doctor.com/storing-data-the-simple-html5-way-and-a-few-tricks-you-might-not-have-known/
http://diveintohtml5.info/storage.html

A separate comment will focus on how to represent the data.

[david-a-wheeler]

Data representation in Javascript is often done with JSON, but that won't work directly. The data to be represented includes function definitions and recursive/cyclic object references; JSON supports neither.

If all we needed was JSON+function function definitions, those are easy. Jsonfn at https://github.com/vkiryukhin/jsonfn shows how. (MIT license, Copyright (c) 2014 Vadim Kiryukhin ( vkiryukhin @ gmail.com )). In short:

   jsonlike_stringify_old: function(obj) {
           return JSON.stringify(obj, function (key, value) {
                   if (value instanceof Function ||
                       typeof value == 'function') {
                           return value.toString();
                   }
                   if (value instanceof RegExp) {
                           return '_PxEgEr_' + value;
                   }
                   return value;
           });
   },

That's not enough for cyclic references, though. A discussion on how to also deal with cyclic references is here:
http://stackoverflow.com/questions/9382167/serializing-object-that-contains-cyclic-object-value