Initial Commit

src/cljs/emptyhead/idea/crud.cljs

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+(ns emptyhead.idea.crud
+  "Functions for Creating, Updating and Deleting ideas.
+  The 'R' in 'CRUD' is implemented by [[emptyhead.idea.protocol/value]]."
+  (:require [emptyhead.idea.state :refer [state]]
+            [emptyhead.idea.property :as prop]
+            [emptyhead.idea.protocol :as prtc]))
+
+(defn- register-idea!
+  "Helper function to scaffold an 'empty' idea."
+  [ref]
+  (swap! state assoc-in [ref :_meta :_properties] #{})
+  (swap! state assoc-in [ref :_meta :_reference] ref)
+  ref)
+
+(defn swap-idea!
+  "Swap data inside `idea` with given `data`.
+  Returns a reference to `idea`."
+  [idea data]
+  (swap! state assoc
+         (prtc/reference idea)
+         (merge data {:_meta (prtc/val-fn :_meta idea)}))
+  (prtc/reference idea))
+
+(defn extend-idea!
+  "Merge `data` into state of `idea`.
+  Returns a reference to `idea`."
+  [idea data]
+  (swap! state assoc (prtc/reference idea) (prtc/val-fn merge idea data))
+  (prtc/reference idea))
+
+(defn mutate-idea!
+  "Evaluate `fun` on `idea` with optional extra `args`, then replace `idea` by the result.
+  Returns a reference to `idea`."
+  [fun idea & args]
+  (swap-idea! idea (prtc/val-fn fun idea args))
+  (prtc/reference idea))
+
+(defn forget-idea!
+  "Delete `idea` from the state.
+  Returns a copy of the `idea`."
+  [idea]
+  (let [val (prtc/value idea)]
+    (apply prop/remove-property! idea (prop/properties idea))
+    (prtc/ref-fn #(swap! state dissoc %) idea)
+    (prtc/copy val)))
+
+(defn have-idea!
+  "Instantiate up to `count` new ideas, optionally prefixing reference symbol with `prefix`.
+  Additionally allows you to immediately attach `properties` and `data`.
+  Returns a single idea or a list of ideas depending on whether `count` was given."
+  [& {:keys [prefix count properties data]
+      :or {count 1 prefix "idea_" properties []}}]
+  (let [fun #(register-idea! (gensym prefix))
+        ideas (take count (repeatedly fun))]
+    (run! #(apply prop/register-property! % properties) ideas)
+    (when data (run! #(extend-idea! % data) ideas))
+    (if (= count 1)
+      (first ideas)
+      ideas)))