1 files changed, 39 insertions, 4 deletions
diff --git a/lib/array.fnl b/lib/array.fnl
index 11e4d2a..9ed0d80 100644
--- a/lib/array.fnl
+++ b/lib/array.fnl
@@ -4,10 +4,45 @@
   (local copy
    (fn [a b]
      (reduce
-      (fn [_ v c]
-       (table.insert c v)
-       c)
+      (fn [_ v res]
+       (table.insert res v)
+       res)
       b a)))
   (copy a b))
 
-{: concat}
+(fn flip [a]
+  (collect [k v (pairs a)]
+    (values v k)))
+
+(fn diff [a b]
+  (local flip-b (flip b))
+  (reduce
+    (fn [_ v res]
+      (when (not (. flip-b v))
+        (table.insert res v))
+      res)
+    a []))
+
+(fn unique [a]
+  (var hash {})
+  (reduce
+    (fn [_ v res]
+      (when (not (. hash v))
+        (tset hash v true)
+        (table.insert res v))
+      res)
+    a []))
+
+(fn flatten [a]
+ (reduce
+  (fn [_ value rest]
+    (concat
+      rest
+      (if (= (type value) "table")
+        (flatten value)
+        [value])))
+  a []))
+
+(local join table.concat)
+
+{: concat : diff : unique : flatten : join}