Add atoms.

ideaboard.txt

@@ -1,7 +1,6 @@
 Concepts / Language Features
 =====
 Agents
-Atoms
 Vars
 state identity lifetime
 lazy sequences

src/koans/atoms.clj

@@ -0,0 +1,31 @@
+(def atomic-clock (atom 0))
+
+(meditations
+  "Atoms are like refs"
+  (= __ @atomic-clock)
+
+  "You can change at the swap meet"
+  (= __ (do
+          (swap! atomic-clock inc)
+          @atomic-clock))
+
+  "Keep taxes out of this: swapping requires no transaction"
+  (= 5 (do
+         __
+         @atomic-clock))
+
+  "Any number of arguments might happen during a swap"
+  (= __ (do
+          (swap! atomic-clock + 1 2 3 4 5)
+          @atomic-clock))
+
+  "Atomic atoms are atomic"
+  (= __ (do
+          (compare-and-set! atomic-clock 100 :fin)
+          @atomic-clock))
+
+  "When your expectations are aligned with reality things, proceed that way"
+  (= :fin (do
+            (compare-and-set! __ __ __)
+            @atomic-clock))
+  )

src/path_to_answer_sheet.clj

@@ -144,6 +144,14 @@
                  ]
            "___" ['(fn [x] (+ 20 x))]}
 
+   "atoms" {"__" [0
+                  1
+                  '(swap! atomic-clock (partial + 4))
+                  20
+                  20
+                  'atomic-clock 20 :fin
+                  ]}
+
    "macros" {"__" ['~(first form)
                    '~(nth form 2)
                    'form

src/path_to_enlightenment.clj

@@ -34,6 +34,7 @@
       "recursion"
       "destructuring"
       "refs"
+      "atoms"
       "macros"
       "datatypes"])