1 files changed, 12 insertions, 13 deletions
diff --git a/aoc-2020-gleam/src/util/pos4.gleam b/aoc-2020-gleam/src/util/pos4.gleam
index a96bcca..c2ab1c7 100644
--- a/aoc-2020-gleam/src/util/pos4.gleam
+++ b/aoc-2020-gleam/src/util/pos4.gleam
@@ -1,31 +1,30 @@
 import gleam/list
-import gleam/bool
 import gleam/set.{type Set}
+import ext/setx
 
 pub type Pos4 =
   #(Int, Int, Int, Int)
 
 pub const zero = #(0, 0, 0, 0)
 
-fn directions80() -> Set(Pos4) {
+fn directions81() -> Set(Pos4) {
   set.from_list({
-    use x <- list.flat_map(over: [-1, 0, 1])
-    use y <- list.flat_map(over: [-1, 0, 1])
-    use z <- list.flat_map(over: [-1, 0, 1])
-    use w <- list.flat_map(over: [-1, 0, 1])
-    let pos = #(x, y, z, w)
-    use <- bool.guard(when: pos == zero, return: [])
-    [pos]
+    use x <- list.flat_map([-1, 0, 1])
+    use y <- list.flat_map([-1, 0, 1])
+    use z <- list.flat_map([-1, 0, 1])
+    use w <- list.map([-1, 0, 1])
+    #(x, y, z, w)
   })
 }
 
+fn directions80() -> Set(Pos4) {
+  set.delete(from: directions81(), this: zero)
+}
+
 pub fn add(p1: Pos4, p2: Pos4) -> Pos4 {
   #(p1.0 + p2.0, p1.1 + p2.1, p1.2 + p2.2, p1.3 + p2.3)
 }
 
 pub fn neighbours80(p: Pos4) -> Set(Pos4) {
-  directions80()
-  |> set.to_list
-  |> list.map(with: add(p, _))
-  |> set.from_list
+  setx.map(directions80(), with: add(p, _))
 }