1 files changed, 18 insertions, 0 deletions
diff --git a/lib/space-is-neighbor.fnl b/lib/space-is-neighbor.fnl
new file mode 100644
index 0000000..380607c
--- /dev/null
+++ b/lib/space-is-neighbor.fnl
@@ -0,0 +1,18 @@
+(local {: contains} (require :lib.contains))
+(local {: head} (require :lib.head))
+(local {: tail} (require :lib.tail))
+
+(lambda space-is-neighbor? [all-neighbors from to]
+  ;; i have learned to check that i'm passing the correct type of move
+  ;; i.e. a number and not a string
+  (assert (= "number" (type from)) "from must be a number")
+  (assert (= "number" (type to)) "to must be a number")
+  (assert (= "table" (type all-neighbors)) "all-neighbors must be a table")
+
+  (let [neighborhood-list (icollect [_ n (ipairs all-neighbors)] (if (= from (head n)) n))
+        neighborhood (head neighborhood-list)
+        neighbors (tail neighborhood)
+        is-neighbor (contains neighbors to)]
+    is-neighbor))
+
+{: space-is-neighbor?}