day 3 part 2

solutions/day03/example2.txt

@@ -0,0 +1 @@
+xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))

solutions/day03/solution.nim

@@ -3,12 +3,9 @@ import aoc
 
 proc parseInstruction(i: string): (int, int) =
   let s =  i.split(',')
-  echo s
   assert s.len == 2
   result = (parseInt(s[0]), parseInt(s[1]))
 
-
-
 proc parseInput(input: string): seq[(int, int)] =
   var i: int
   while i < input.len:
@@ -35,21 +32,59 @@ proc parseInput(input: string): seq[(int, int)] =
         inc i
     else: inc i
 
-
-      # var xy: (int, int)
-
-
 proc partOne*(input: string): int =
   let instructions = parseInput(input)
   instructions.mapIt(it[0] * it[1]).sum()
 
+proc parseInput2(input: string): seq[(int, int)] =
+  var i: int
+  var working = true
+  while i < input.len:
+    case input[i]
+    of 'd':
+      # check for enough room for don't()
+      if i > (input.len - 6): inc i
+      else:
+        if input[i .. i + 3] == "do()":
+          working = true
+          i += 3
+        elif input[i .. i + 6] == "don't()":
+          working = false
+          i += 6
+        inc i
+    of 'm':
+      # ul(x,y)
+      # not enough space for instruction so bail
+      if i > (input.len - 6): return
+      else:
+        var instruction: string
+        if input[i .. i+3] == "mul(":
+          i += 4
+          while true:
+            let c = input[i]
+            case c:
+              of '0'..'9':
+                instruction.add c; inc i
+              of ')':
+                if working:
+                  result.add parseInstruction instruction
+                break
+              of ',':
+                instruction.add c; inc i
+              else: break
+        inc i
+    else: inc i
+
+
+proc partTwo*(input: string): int =
+  let instructions = parseInput2(input)
+  instructions.mapIt(it[0] * it[1]).sum()
 
-# proc partTwo*(input: string): int = 0
-#
 solve:
   "example.txt":
     partOne: 161
-    # partTwo: 0
+  "example2.txt":
+    partTwo: 48
   "input.txt":
-    partOne: 0
+    partOne: 164730528
-  #   partTwo: 0
+    partTwo: 70478672