Not much done, and, to be honest, I'm not even sure it's an improvement.

src/cljs/mw3/core.cljs

@@ -1,17 +1,45 @@
 (ns ^:figwheel-always mw3.core
   (:require-macros [cljs.core.async.macros :refer [go]])
-  (:require [om.core :as om :include-macros true]
-            [om.dom :as dom :include-macros true]
-            [cljs.core.async :refer [put! chan <!]]
-            [clojure.string :as string]
-            [secretary.core :as sec :include-macros true]
-            [goog.events :as events]
-            [goog.history.EventType :as EventType]
-            [dommy.core :as dommy :refer-macros [sel sel1]])
-  (:import goog.History))
+  (:require
+    [mw3.rulesets :as rulesets]
+    [dommy.core :as dommy :refer-macros [sel sel1]]
+    [dommy.template :as temp]))
 
-(def pages [:#home-content :#params-content :#rules-content :#world-content :#docs-content])
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Data declarations
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+;; Tiles supplied in the standard distribution. Obviously this isn't all the states you can have.
+(def tiles ["abandoned"
+            "black"
+            "camp"
+            "climax"
+            "crop"
+            "error"
+            "fire"
+            "forest"
+            "grassland"
+            "heath"
+            "house"
+            "ice"
+            "inn"
+            "market"
+            "meadow"
+            "pasture"
+            "plague"
+            "ploughland"
+            "scrub"
+            "snow"
+            "waste"
+            "water"
+            "white"])
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Navigation
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+;; Tabs in the single-page app.
 (def available-tabs {:#home-tab {:content :#home-content :text "Home"}
                      :#params-tab {:content :#params-content :text "Parameters"}
                      :#rules-tab {:content :#rules-content :text "Rules"}
@@ -31,11 +59,34 @@
 (defn tab-click-listener
   "Set up a click listener on the tab with this `tab-id`"
   [tab-id]
+  (dommy/set-text! (sel1 tab-id) (:text (tab-id available-tabs)))
   (dommy/listen! (sel1 tab-id) :click (fn [e] (tab-handler e tab-id))))
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Rules page
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(defn load-ruleset
+  [name]
+)
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Set up the screen on loading
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
 ;; listeners for the tab bar
 (tab-click-listener :#home-tab)
 (tab-click-listener :#params-tab)
 (tab-click-listener :#rules-tab)
 (tab-click-listener :#world-tab)
 (tab-click-listener :#docs-tab)
+
+;; hide controls which aren't needed if we're doing things client side
+(doseq [to-hide (sel :.hide-if-active)]
+  (dommy/set-style! to-hide :display "none"))
+
+;; hide all pages except home-tab
+(tab-handler nil :#home-tab)
+
+;; put the default ruleset into the rulesets pages
+(dommy/set-text! (sel1 :#rules-src) (rulesets/ruleset-as-single-string "ice-age"))

src/cljs/mw3/rulesets.cljs

@@ -2,6 +2,7 @@
 
 ;; Map of available rulesets. Key is a string name of the ruleset; value is a sequence of strings
 ;; of rule text.
+
 (def rulesets
   {"ice-age" [
               "# Ice Age"
@@ -30,3 +31,10 @@
                  ;; and, again, so on.
                 ]
    })
+
+
+(defn ruleset-as-single-string
+  "Return the ruleset with this `name` as a single string."
+  [name]
+  (str (interleave (rulesets name) (repeat "\n"))))
+