From 5e555d94508037ffe3a4b58b6d1660925887e342 Mon Sep 17 00:00:00 2001
From: Matt Russell <MattRussellUK@gmail.com>
Date: Tue, 3 Dec 2024 18:50:04 +0000
Subject: [PATCH] wip

---
 Aoc2024/Day03/Solve.lean | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/Aoc2024/Day03/Solve.lean b/Aoc2024/Day03/Solve.lean
index 4d48d8a..4542d36 100644
--- a/Aoc2024/Day03/Solve.lean
+++ b/Aoc2024/Day03/Solve.lean
@@ -3,6 +3,8 @@ import Aoc2024.Day03.Examples
 import Aoc2024.Day03.Parser
 import Aoc2024.Day03.Types
 
+-- Part 1
+
 private def Instruction.value : Instruction -> Int
   | Instruction.mul n m => n * m
   | _ => 1
@@ -11,23 +13,24 @@ def solvePart1 (s : String) : Int := findInstructions s |>.sumBy (·.value)
 
 #guard solvePart1 exampleInputPart1 == 161
 
+-- Part 2
+
 private structure State where
   isEnabled: Bool
   enabledMuls: List Instruction
 
-def State.enable (s : State): State := { s with isEnabled := true }
-def State.disable (s : State): State := { s with isEnabled := false }
-def State.recordMul (instruction : Instruction) (s : State): State :=
+private def State.enable (s : State): State := { s with isEnabled := true }
+private def State.disable (s : State): State := { s with isEnabled := false }
+private def State.recordMul (instruction : Instruction) (s : State): State :=
   { s with enabledMuls := instruction :: s.enabledMuls }
-def State.initial: State := { isEnabled := true, enabledMuls := [] }
-
-private def processInstruction (instruction: Instruction): StateM State Unit :=
-  match instruction with
-    | Instruction.mul _ _ => do
-        if (<- get).isEnabled then
-          modify (State.recordMul instruction)
-    | Instruction.do => modify State.enable
-    | Instruction.dont => modify State.disable
+private def State.initial: State := { isEnabled := true, enabledMuls := [] }
+
+private def processInstruction : Instruction -> StateM State Unit
+  | i@(Instruction.mul _ _) => do
+      if (<- get).isEnabled then
+        modify (State.recordMul i)
+  | Instruction.do => modify State.enable
+  | Instruction.dont => modify State.disable
 
 private def getEnabledMuls (instructions : List Instruction) : List Instruction :=
   instructions.forM processInstruction |>.run State.initial |>.snd.enabledMuls