Shared.hierarchicalize: Don't number subsections of unnumbered sections.

They were previously numbered, starting from the previous numbered
section, which was wrong.

src/Text/Pandoc/Shared.hs

@@ -105,7 +105,7 @@ import System.FilePath ( (</>), takeExtension, dropExtension )
 import Data.Generics (Typeable, Data)
 import qualified Control.Monad.State as S
 import qualified Control.Exception as E
-import Control.Monad (msum, unless)
+import Control.Monad (msum)
 import Text.Pandoc.Pretty (charWidth)
 import System.Locale (defaultTimeLocale)
 import Data.Time
@@ -615,25 +615,32 @@ inlineListToIdentifier =
 
 -- | Convert list of Pandoc blocks into (hierarchical) list of Elements
 hierarchicalize :: [Block] -> [Element]
-hierarchicalize blocks = S.evalState (hierarchicalizeWithIds blocks) []
+hierarchicalize blocks = S.evalState (hierarchicalizeWithIds True blocks) []
 
-hierarchicalizeWithIds :: [Block] -> S.State [Int] [Element]
-hierarchicalizeWithIds [] = return []
-hierarchicalizeWithIds ((Header level attr@(_,classes,_) title'):xs) = do
-  lastnum <- S.get
-  let lastnum' = take level lastnum
-  let newnum = case length lastnum' of
-                    x | "unnumbered" `elem` classes -> []
-                      | x >= level -> init lastnum' ++ [last lastnum' + 1]
-                      | otherwise -> lastnum ++
-                           replicate (level - length lastnum - 1) 0 ++ [1]
-  unless (null newnum) $ S.put newnum
+hierarchicalizeWithIds :: Bool -> [Block] -> S.State [Int] [Element]
+hierarchicalizeWithIds _ [] = return []
+hierarchicalizeWithIds number ((Header level attr@(_,classes,_) title'):xs) = do
+  let number' = number && "unnumbered" `notElem` classes
+  newnum <- if number'
+               then do
+                 lastnum <- S.get
+                 let lastnum' = take level lastnum
+                 let n = case length lastnum' of
+                               x | x >= level -> init lastnum' ++
+                                         [last lastnum' + 1]
+                                 | otherwise -> lastnum ++
+                                      replicate (level -
+                                        length lastnum - 1) 0 ++ [1]
+                 S.put n
+                 return n
+               else return []
   let (sectionContents, rest) = break (headerLtEq level) xs
-  sectionContents' <- hierarchicalizeWithIds sectionContents
-  rest' <- hierarchicalizeWithIds rest
+  -- ensure that subsections of an unnumbered section aren't numbered
+  sectionContents' <- hierarchicalizeWithIds number' sectionContents
+  rest' <- hierarchicalizeWithIds number rest
   return $ Sec level newnum attr title' sectionContents' : rest'
-hierarchicalizeWithIds (x:rest) = do
-  rest' <- hierarchicalizeWithIds rest
+hierarchicalizeWithIds number (x:rest) = do
+  rest' <- hierarchicalizeWithIds number rest
   return $ (Blk x) : rest'
 
 headerLtEq :: Int -> Block -> Bool