z/leftmost tracks position correctly

Author: eraserhd

src/rewrite_clj/zip/zip.clj

@@ -131,10 +131,12 @@
   [loc]
   (let [{:keys [node parent left right]} loc]
     (if (and parent (seq left))
-      (assoc loc
-             :node (ffirst left)
-             :left []
-             :right (concat (map first (rest left)) [node] right))
+      (let [[lnode lpos] (first left)]
+        (assoc loc
+               :node lnode
+               :position lpos
+               :left []
+               :right (concat (map first (rest left)) [node] right)))
       loc)))
 
 (defn insert-left

test/rewrite_clj/zip/zip_test.clj

@@ -58,3 +58,10 @@
   1  [1 7]
   2  [1 4]
   3  [1 1])
+
+(fact "z/leftmost tracks position correctly"
+  (-> (base/of-string "[hello world]")
+    z/down
+    z/right z/right
+    z/leftmost
+    z/position) => [1 2])