Update design doc

Author: Tko1

clojureRS.org

@@ -160,3 +160,34 @@ Perhaps they could look like
  'offshoots' of, say, intern in this case (although its basically namespacing
  in a way; anytime you're doing something like blah__1 blah__other blah__3, 
  your blah has become a 'family name' of sorts; a namespace). 
+** Immutable Data Structures 
+ Right now we likewise use naive immutables; the map is an O(n) associative-list, 
+ meaning its really a list of (key . value) pairs underneath, and a persistent 'history' 
+ is achieved by thinking of the list as a timeline of changes; the first element 
+ is the first change, the second the second, and if you hold the map as it was at this 
+ point in time, you simply point to this second entry. Then, to search for members of the map,
+ you walk backwards through the timeline -- but not forwards; things will continue to happen, but 
+ they won't affect you because they'll come afterwards.
+
+ The persistent vector is just a plain Vec, and more importantly I
+ don't think there's any structural sharing there atm
+
+ The persistent list should be the closest to the proper Clojure structure, and is a Cons list, where 
+ likewise what sublist you reference depends on where your head is pointing to. 
+
+ The plan is to look into `im` or implement the structures myself, if I find that's necessary. I already
+ started reverse engineering the PersistentHashMap myself, trying to come up with a structure with the 
+ same time / space complexities, although I will definitely not wait for me to figure that out --
+ that could take weeks or years or forever -- I'll just look it up. But I'd be neato if I did 
+** Memory management 
+ Right now, the project uses plain, also-naive reference counting.
+ Things in the ClojureRS world live inside Rc<Values> , where Value
+ (again) is an enum wrapping all potential types.
+
+ It will be important for this to truly grow, I think, before we start trying to observe it under 
+ the hood, mapping its activities to visuals that show us just 
+ what kind of dance is going on underneath, and where the bottlenecks are. 
+
+ It will be at that time that it will be best to truly start adding
+ a deeper design to memory management, although until then I will
+ keep reading on what others have found before me