2 files changed, 13 insertions, 17 deletions

diff --git a/samples/aoc/2020/01/solve.bruijn b/samples/aoc/2020/01/solve.bruijn
index 7e4c0d2..c3eb669 100644
--- a/samples/aoc/2020/01/solve.bruijn
+++ b/samples/aoc/2020/01/solve.bruijn
@@ -1,22 +1,9 @@
-# TODO: While this obviously isn't the most performant solution, it should still
-#       be a lot faster than it currently is. I think there's some problem with
-#       underlying strictness/laziness
-
 :import std/Combinator .
 :import std/String .
 :import std/Math .
-:import std/Pair P
-
-part1 z [[rec]]
-	rec ((P.uncurry …+… ^0) =? (+2020)) case-done case-cont
-		case-done P.uncurry …⋅… ^0
-		case-cont 1 ~0
 
-part2 z [[rec]]
-	rec (∑(^0) =? (+2020)) case-done case-cont
-		case-done ∏(^0)
-		case-cont 1 ~0
+solve (find (sum → (eq? (+2020)))) → product
 
-main [parts nums]
-	nums string→number <$> ~(<~>(lines 0))
-	parts [(part1 (cross 0 0)) : (part2 (cross3 0 0 0))]
+main trim → lines → (map string→number) → (φ (cons ⋔ solve) part1 part2)
+	part1 [[[~1 : {}0] <$> (drop ^0 1)] <++> (enumerate 0)]
+	part2 [[[[~2 : (~1 : {}0)] <$> (drop ^0 2)] <++> (enumerate (drop ^0 1))] <++> (enumerate 0)]
diff --git a/std/List.bruijn b/std/List.bruijn
index ed16530..09b16f9 100644
--- a/std/List.bruijn
+++ b/std/List.bruijn
@@ -457,6 +457,15 @@ find-index z [[[rec]]] ⧗ (a → Boolean) → (List a) → Number
 :test (find-index (…=?… (+2)) ((+1) : ((+2) : ((+3) : {}(+2))))) ((+1))
 :test (find-index (…=?… (+4)) ((+1) : ((+2) : ((+3) : {}(+2))))) ((-1))
 
+# finds the first element that matches a predicate
+find z [[[rec]]] ⧗ (a → Boolean) → (List a) → a
+	rec 0 [[[case-find]]] case-end
+		case-find (4 2) 2 (5 4 1)
+		case-end Ω
+
+:test (find (…=?… (+2)) ((+1) : ((+2) : ((+3) : {}(+2))))) ((+2))
+:test (find (…=?… (+1)) ((+1) : ((+2) : ((+3) : {}(+2))))) ((+1))
+
 # removes first element that matches an eq predicate
 remove z [[[[rec]]]] ⧗ (a → a → Boolean) → a → (List a) → (List a)
 	rec 0 [[[case-remove]]] case-end