- add re-frame as a project dependency

- move model/db , handlers & history from dj-scratchpad to re-frame
- introduce priviliged protocol history/reset-history! and call from bootstrap
- convert all requires to use new re-frame/handlers
- introduce demo.bootstrap to init system and trigger handler registrations (removed redundant requires elsewhere).
- call bootsrap from main.cljs
- update unit tests

project.clj

@@ -4,7 +4,8 @@
 
   :dependencies [[org.clojure/clojure "1.6.0"]
                  [org.clojure/clojurescript "0.0-2322"]
-                 [reagent "0.4.3"]]
+                 [reagent "0.4.3"]
+                 [historian "1.0.7"]]
 
   :profiles     {:debug {:debug true}
                  :dev {:dependencies [[spellhouse/clairvoyant "0.0-48-gf5e59d3"]]
@@ -24,7 +25,7 @@
   :jar-exclusions [#"(?:^|\/)re-frame-demo\/"]
 
   :cljsbuild    {:builds [{:id "demo"
-                           :source-paths   ["src/demo" "src/re_frame"]
+                           :source-paths   ["src" "src/re_frame"]
                            :compiler       {:output-to     "run/compiled/demo.js"
                                             :source-map    "run/compiled/demo.js.map"
                                             :output-dir    "run/compiled/demo"

src/re_frame/core.cljs

@@ -1,4 +0,0 @@
-(ns re-frame.core
-  (:require [reagent.core :as  reagent]
-            ))
-

src/re_frame/db.cljs

@@ -0,0 +1,11 @@
+(ns re-frame.db
+  (:require [reagent.core :as r]))
+
+  ;; -- application data ---------------------------------------------------------------------------
+  ;;
+  ;; The entire state of the application is stored in this one atom.
+  ;; It is useful to think of this atom as a database, hence its name.
+  ;; For example, when it is mutated, we want it done in "a transaction", so it never appears in
+  ;; an inconsistent state. Atomic operations, etc.
+
+  (def ^:private db (r/atom {}))

src/re_frame/handlers.cljs

@@ -1,4 +1,5 @@
- (ns model.handlers)
+ (ns re-frame.handlers
+   (:require [re-frame.db :refer [db]]))
 
 
  ;; -- helpers ------------------------------------------------------------------------------------
@@ -25,14 +26,12 @@
                validation-fn))))
 
 
-;; -- application data ---------------------------------------------------------------------------
-;;
-;; The entire state of the application is stored in this one atom.
-;; It is useful to think of this atom as a database, hence its name.
-;; For example, when it is mutated, we want it done in "a transaction", so it never appears in
-;; an inconsistent state. Atomic operations, etc.
-;;
-(def ^:private db                (atom nil))
+ (defn get-in-db
+   "Direct lookup of arbitrary path in state/db without subscription/reaction.
+    NOTE: While it is convenient to not have to pass values through function chains,
+          by definition this also incourages non pure functional style, so resist."
+   [path-v]
+   (get-in @db path-v))
 
 
 ;; -- Event Handlers ------------------------------------------------------------------------------
@@ -84,12 +83,12 @@
 
 
 ;; reagent components call this function when they want to "send" an event.
-(defn dispatch                     ;; TODO: call it  (dispatch-event [])
+(defn dispatch
  [event-v]                         ;;  something like  [:delete-item  42]
  (let [event-id    (first-in-vector event-v)
        handler-fn  (get @event-id->handler-fn event-id)]
    (assert (not (nil? handler-fn)) (str "No event handler registered for event: " event-id ))
-   (handler-fn @db event-v)))
+   (handler-fn db event-v)))
 
 
 
@@ -119,19 +118,20 @@
 (def ^:private subscription-key->handler-fn (atom {}))
 
 
- (defn register-subscription
-   [key-v handler-fn]
-   (if (contains? @subscription-key->handler-fn key-v)
-     (println "Warning: overwritting a subscription-handler: " key-v))     ;; TODO: more generic logging
-   (swap! subscription-key->handler-fn assoc key-v handler-fn))
+(defn register-subscription
+  [key-v handler-fn]
+  (if (contains? @subscription-key->handler-fn key-v)
+    (println "Warning: overwritting a subscription-handler: " key-v))     ;; TODO: more generic logging
+  (swap! subscription-key->handler-fn assoc key-v handler-fn))
 
 
- (defn subscribe
-   "returns a reagent/reaction which observes a part of the "
-   [v]
-   (let [key-v       (first-in-vector v)
-         handler-fn  (get @subscription-key->handler-fn key-v)]
-     (assert (not (nil? handler-fn)) (str "No subscription handler registered for key: " key-v))
-     (handler-fn @db v)))
+(defn subscribe
+  "returns a reagent/reaction which observes a part of the "
+  [v]
+  (let [key-v       (first-in-vector v)
+        handler-fn  (get @subscription-key->handler-fn key-v)]
+    (assert (not (nil? handler-fn)) (str "No subscription handler registered for key: " key-v))
+    (handler-fn db v)))
+
 
 

src/re_frame/history.cljs

@@ -0,0 +1,62 @@
+ (ns re-frame.history
+   (:require-macros [reagent.ratom  :refer [reaction]]
+                    [historian.core :refer [off-the-record]])
+   (:require
+     [reagent.core      :as r]
+     [re-frame.db :refer [db]]
+     [re-frame.handlers :refer [register-subscription register-handler]]
+     [historian.core    :as    historian]
+     ))
+
+
+ ;; -- History -----------------------------------------------------------
+ ;; https://day8.slack.com/files/mikhug/F03238WLX/historian.md
+
+ (historian/record! db :db)
+ (def undo-list (r/atom []))
+ (def redo-list (r/atom []))
+ (historian/replace-library!  undo-list)
+ (historian/replace-prophecy! redo-list)
+
+ (defn reset-history!
+   "privileged protocol: should not be used by client code"
+   []
+   (historian/clear-history!)
+   (historian/trigger-record!))
+
+ (register-subscription
+   :undos?
+   (fn
+     [_ _]
+     "answer true is anything is stored in the undo list"
+     (reaction (> (count @undo-list) 1))))
+
+ (register-subscription
+   :redos?
+   (fn
+     [_ _]
+     "answer true is anything is stored in the redo list"
+     (reaction (> (count @redo-list) 0))))
+
+ ;; -------------------------- HANDLERS ----------------------------------------
+
+ (register-handler
+   :undo
+   (fn
+     [_ _]
+     (historian/undo!))) ;; (dispatch [:undo])
+
+
+ (register-handler
+   :redo
+   (fn
+     [_ _]
+     (historian/redo!))) ;; (dispatch [:undo])
+
+
+  (register-handler
+   :no-history-while
+   (fn
+     [db [_ mutation-fn]]
+     (off-the-record
+       (reset! db (mutation-fn @db)))))