Day 18, now with corrected comment

src/AOC-18a.hs

@@ -34,9 +34,9 @@ explode sn = case iter 1 sn of
   Nothing -> Nothing
   Nothing -> Nothing
   Just (result, _, _) -> Just result
   Just (result, _, _) -> Just result
   where
   where
-  -- the second coordinate of the result encodes whether a 
-  -- reduction occured, and if so, what numbers might need to
-  -- be added to the left or right.
+  -- The outer Maybe wrapper encodes if a reduction occurred, and the
+  -- inner Maybe wrappers encode if a number need to be added to the
+  -- left and/or right sides of the number being constructed.
   iter :: Int -> SFNumber -> Maybe (SFNumber, Maybe Int, Maybe Int)
   iter :: Int -> SFNumber -> Maybe (SFNumber, Maybe Int, Maybe Int)
   iter _ (Regular _) = Nothing
   iter _ (Regular _) = Nothing
   iter 5 (Pair (Regular x) (Regular y)) =
   iter 5 (Pair (Regular x) (Regular y)) =

src/AOC-18b.hs

@@ -35,9 +35,9 @@ explode sn = case iter 1 sn of
   Nothing -> Nothing
   Nothing -> Nothing
   Just (result, _, _) -> Just result
   Just (result, _, _) -> Just result
   where
   where
-  -- the second coordinate of the result encodes whether a 
-  -- reduction occured, and if so, what numbers might need to
-  -- be added to the left or right.
+  -- The outer Maybe wrapper encodes if a reduction occurred, and the
+  -- inner Maybe wrappers encode if a number need to be added to the
+  -- left and/or right sides of the number being constructed.
   iter :: Int -> SFNumber -> Maybe (SFNumber, Maybe Int, Maybe Int)
   iter :: Int -> SFNumber -> Maybe (SFNumber, Maybe Int, Maybe Int)
   iter _ (Regular _) = Nothing
   iter _ (Regular _) = Nothing
   iter 5 (Pair (Regular x) (Regular y)) =
   iter 5 (Pair (Regular x) (Regular y)) =