Move compactify'DL from Markdown reader into Shared

The function `compactify'DL`, used to change the final definition item of a
definition list into a `Plain` iff all other items are `Plain`s as well, is
useful in many parsers and hence moved into Text.Pandoc.Shared.

src/Text/Pandoc/Readers/Markdown.hs

@@ -861,22 +861,6 @@ definitionList = do
   items <- fmap sequence $ many1 definitionListItem
   return $ B.definitionList <$> fmap compactify'DL items
 
-compactify'DL :: [(Inlines, [Blocks])] -> [(Inlines, [Blocks])]
-compactify'DL items =
-  let defs = concatMap snd items
-      defBlocks = reverse $ concatMap B.toList defs
-      isPara (Para _) = True
-      isPara _        = False
-  in  case defBlocks of
-           (Para x:_) -> if not $ any isPara (drop 1 defBlocks)
-                            then let (t,ds) = last items
-                                     lastDef = B.toList $ last ds
-                                     ds' = init ds ++
-                                          [B.fromList $ init lastDef ++ [Plain x]]
-                                  in init items ++ [(t, ds')]
-                            else items
-           _          -> items
-
 --
 -- paragraph block
 --
@@ -1892,4 +1876,3 @@ doubleQuoted = try $ do
   (withQuoteContext InDoubleQuote $ doubleQuoteEnd >> return
        (fmap B.doubleQuoted . trimInlinesF $ contents))
    <|> (return $ return (B.str "\8220") <> contents)
-

src/Text/Pandoc/Shared.hs

@@ -56,6 +56,7 @@ module Text.Pandoc.Shared (
                      stringify,
                      compactify,
                      compactify',
+                     compactify'DL,
                      Element (..),
                      hierarchicalize,
                      uniqueIdent,
@@ -82,7 +83,7 @@ module Text.Pandoc.Shared (
 import Text.Pandoc.Definition
 import Text.Pandoc.Walk
 import Text.Pandoc.Generic
-import Text.Pandoc.Builder (Blocks, ToMetaValue(..))
+import Text.Pandoc.Builder (Inlines, Blocks, ToMetaValue(..))
 import qualified Text.Pandoc.Builder as B
 import qualified Text.Pandoc.UTF8 as UTF8
 import System.Environment (getProgName)
@@ -435,6 +436,21 @@ compactify' items =
                             _   -> items
            _      -> items
 
+-- | Like @compactify'@, but akts on items of definition lists.
+compactify'DL :: [(Inlines, [Blocks])] -> [(Inlines, [Blocks])]
+compactify'DL items =
+  let defs = concatMap snd items
+      defBlocks = reverse $ concatMap B.toList defs
+  in  case defBlocks of
+           (Para x:_) -> if not $ any isPara (drop 1 defBlocks)
+                            then let (t,ds) = last items
+                                     lastDef = B.toList $ last ds
+                                     ds' = init ds ++
+                                          [B.fromList $ init lastDef ++ [Plain x]]
+                                  in init items ++ [(t, ds')]
+                            else items
+           _          -> items
+
 isPara :: Block -> Bool
 isPara (Para _) = True
 isPara _        = False
@@ -698,5 +714,3 @@ safeRead s = case reads s of
                   (d,x):_
                     | all isSpace x -> return d
                   _                 -> fail $ "Could not read `" ++ s ++ "'"
-
-