Implement 2024 day 3 part 2 in Terraform

No one's going to stop me, not even common sense

2024/bonus/day03/main.tf

@@ -4,8 +4,21 @@ variable "input" {
 
 locals {
   muls = regexall("mul\\((\\d+),(\\d+)\\)", var.input)
+  ops  = regexall("(don't\\(\\)|do\\(\\)|mul\\((\\d+),(\\d+)\\))", var.input)
+}
+
+module "should_execute" {
+  count  = length(local.ops)
+  source = "./should_execute"
+
+  index = count.index
+  ops   = local.ops
 }
 
 output "part1" {
   value = sum([for mul in local.muls : parseint(mul[1], 10) * parseint(mul[0], 10)])
 }
+
+output "part2" {
+  value = sum(module.should_execute[*].value)
+}

2024/bonus/day03/should_execute/main.tf

@@ -0,0 +1,19 @@
+variable "ops" {
+  type = list(list(string))
+}
+
+variable "index" {
+  type = number
+}
+
+locals {
+  is_mul   = startswith(var.ops[var.index][0], "mul")
+  subslice = reverse(slice(var.ops[*][0], 0, var.index))
+
+  do_pos   = contains(local.subslice, "do()") ? index(local.subslice, "do()") : var.index
+  dont_pos = contains(local.subslice, "don't()") ? index(local.subslice, "don't()") : var.index + 1
+}
+
+output "value" {
+  value = (local.is_mul && local.do_pos < local.dont_pos) ? (parseint(var.ops[var.index][1], 10) * parseint(var.ops[var.index][2], 10)) : 0
+}

2024/bonus/main.tf

@@ -36,3 +36,7 @@ module "day03" {
 output "day03_1" {
   value = module.day03.part1
 }
+
+output "day03_2" {
+  value = module.day03.part2
+}

2024/bonus/tests.tftest.hcl

@@ -57,3 +57,20 @@ run "day3_1" {
     error_message = "Part1 output is wrong"
   }
 }
+
+run "day3_2" {
+  command = plan
+
+  module {
+    source = "./day03"
+  }
+
+  variables {
+    input = "xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))"
+  }
+
+  assert {
+    condition     = output.part2 == 48
+    error_message = "Part2 output is wrong"
+  }
+}