Experimenting with defprotocol and defrecord.

src/the_great_game/agent/agent.clj

@@ -1,7 +1,43 @@
 (ns the-great-game.agent.agent
-  "Anything in the game world with agency")
+  "Anything in the game world with agency"
+  (:require [the-great-game.objects.object :refer [ProtoObject]]
+            [the-great-game.objects.container :refer [ProtoContainer]]))
 
 ;;  hierarchy of needs probably gets implemented here
 ;;  I'm probably going to want to defprotocol stuff, to define the hierarchy
 ;;  of things in the gameworld; either that or drop to Java, wich I'd rather not do.
 
+(defprotocol ProtoAgent
+  "An object which can act in the world"
+  (act
+    [actor world circle]
+       "Allow `actor` to do something in this `world`, in the context of this
+       `circle`; return the new state of the actor if something was done, `nil`
+       if nothing was done. Circle is expected to be one of
+
+       * `:active` - actors within visual/audible range of the player
+         character;
+       * `:pending` - actors not in the active circle, but sufficiently close
+         to it that they may enter the active circle within a short period;
+       * `:background` - actors who are active in the background in order to
+         handle trade, news, et cetera;
+       * `other` - actors who are not members of any other circle, although
+         I'm not clear whether it would ever be appropriate to invoke an
+         `act` method on them.
+
+       The `act` method *must not* have side effects; it must *only* return a
+       new state. If the actor's intention is to seek to change the state of
+       something else in the game world, it must add a representation of that
+       intention to the sequence which will be returned by its
+       `pending-intentions` method.")
+  (pending-intentions
+    [actor]
+    "Returns a sequence of effects an actor intends, as a consequence of
+    acting. The encoding of these is not yet defined."))
+
+;; (defrecord Agent
+;;   "A default agent."
+;;   ProtoObject
+;;   ProtoContainer
+;;   ProtoAgent
+;; )

src/the_great_game/objects/container.clj

@@ -0,0 +1,11 @@
+(ns the-great-game.objects.container
+  (:require
+    [the-great-game.objects.game-object :refer :all]))
+
+(defprotocol ProtoContainer
+  (contents
+    [container]
+            "Return a sequence of the contents of this `container`, or `nil` if empty.")
+  (is-empty?
+    [container]
+    "Return `true` if this `container` is empty, else `false`."))

src/the_great_game/objects/game-object.clj

@@ -0,0 +1,19 @@
+(ns the-great-game.objects.game-object
+  "Anything at all in the game world")
+
+(defprotocol ProtoObject
+  "An object in the world"
+  (id [object] "Returns the unique id of this object.")
+  (reify-object
+    [object]
+    "Adds this `object` to the global object list. If the `object` has a
+    non-nil value for its `id` method, keys it to that id - **but** if the
+    id value is already in use, throws a hard exception. Returns the id to
+    which the object is keyed in the global object list."))
+
+(defrecord GameObject
+  [id]
+  ;; "An object in the world"
+  ProtoObject
+  (id [_] id)
+  (reify-object [object] "TODO: doesn't work yet"))