Org reader: respect drawer export setting

The `d` export option can be used to control which drawers are exported
and which are discarded.  Basic support for this option is added here.

src/Text/Pandoc/Readers/Org.hs

@@ -138,7 +138,7 @@ exportSetting = choice
   , ignoredSetting "author"
   , ignoredSetting "c"
   , ignoredSetting "creator"
-  , ignoredSetting "d"
+  , complementableListSetting "d" setExportDrawers
   , ignoredSetting "date"
   , ignoredSetting "e"
   , ignoredSetting "email"
@@ -164,15 +164,53 @@ booleanSetting :: String -> ExportSettingSetter Bool -> OrgParser ()
 booleanSetting settingIdentifier setter = try $ do
   string settingIdentifier
   char ':'
-  value <- many nonspaceChar
-  let boolValue = case value of
-                    "nil" -> False
-                    "{}"  -> False
-                    _     -> True
-  updateState $ modifyExportSettings setter boolValue
+  value <- elispBoolean
+  updateState $ modifyExportSettings setter value
+
+-- | Read an elisp boolean.  Only NIL is treated as false, non-NIL values are
+-- interpreted as true.
+elispBoolean :: OrgParser Bool
+elispBoolean = try $ do
+  value <- many1 nonspaceChar
+  return $ case map toLower value of
+             "nil" -> False
+             "{}"  -> False
+             "()"  -> False
+             _     -> True
+
+-- | A list or a complement list (i.e. a list starting with `not`).
+complementableListSetting :: String
+                          -> ExportSettingSetter (Either [String] [String])
+                          -> OrgParser ()
+complementableListSetting settingIdentifier setter = try $ do
+  _     <- string settingIdentifier <* char ':'
+  value <- choice [ Left <$> complementStringList
+                  , Right <$> stringList
+                  , (\b -> if b then Left [] else Right []) <$> elispBoolean
+                  ]
+  updateState $ modifyExportSettings setter value
+ where
+   -- Read a plain list of strings.
+   stringList :: OrgParser [String]
+   stringList = try $
+     char '('
+       *> sepBy elispString spaces
+       <* char ')'
+
+   -- Read an emacs lisp list specifying a complement set.
+   complementStringList :: OrgParser [String]
+   complementStringList = try $
+     string "(not "
+       *> sepBy elispString spaces
+       <* char ')'
+
+   elispString :: OrgParser String
+   elispString = try $
+     char '"'
+       *> manyTill alphaNum (char '"')
 
 ignoredSetting :: String -> OrgParser ()
-ignoredSetting s = try (() <$ string s <* char ':' <* many nonspaceChar)
+ignoredSetting s = try (() <$ string s <* char ':' <* many1 nonspaceChar)
 
 --
 -- Parser
@@ -588,11 +626,27 @@ exampleLine = try $ skipSpaces *> string ": " *> anyLine
 --
 
 -- | A generic drawer which has no special meaning for org-mode.
+-- Whether or not this drawer is included in the output depends on the drawers
+-- export setting.
 genericDrawer :: OrgParser (F Blocks)
 genericDrawer = try $ do
-  drawerStart
-  manyTill drawerLine (try drawerEnd)
-  return mempty
+  name    <- map toUpper <$> drawerStart
+  content <- manyTill drawerLine (try drawerEnd)
+  state   <- getState
+  -- Include drawer if it is explicitly included in or not explicitly excluded
+  -- from the list of drawers that should be exported.  PROPERTIES drawers are
+  -- never exported.
+  case (exportDrawers . orgStateExportSettings $ state) of
+    _           | name == "PROPERTIES" -> return mempty
+    Left  names | name `elem`    names -> return mempty
+    Right names | name `notElem` names -> return mempty
+    _                                  -> drawerDiv name <$> parseLines content
+ where
+  parseLines :: [String] -> OrgParser (F Blocks)
+  parseLines = parseFromString parseBlocks . (++ "\n") . unlines
+
+  drawerDiv :: String -> F Blocks -> F Blocks
+  drawerDiv drawerName = fmap $ B.divWith (mempty, [drawerName, "drawer"], mempty)
 
 drawerStart :: OrgParser String
 drawerStart = try $

src/Text/Pandoc/Readers/Org/ParserState.hs

@@ -39,8 +39,9 @@ module Text.Pandoc.Readers.Org.ParserState
   , runF
   , returnF
   , ExportSettingSetter
-  , exportSubSuperscripts
+  , ExportSettings (..)
   , setExportSubSuperscripts
+  , setExportDrawers
   , modifyExportSettings
   ) where
 
@@ -76,6 +77,10 @@ type OrgLinkFormatters = M.Map String (String -> String)
 -- These settings can be changed via OPTIONS statements.
 data ExportSettings = ExportSettings
   { exportSubSuperscripts :: Bool -- ^ TeX-like syntax for sub- and superscripts
+  , exportDrawers         :: Either [String] [String]
+  -- ^ Specify drawer names which should be exported.  @Left@ names are
+  -- explicitly excluded from the resulting output while @Right@ means that
+  -- only the listed drawer names should be included.
   }
 
 -- | Org-mode parser state
@@ -155,6 +160,7 @@ defaultOrgParserState = OrgParserState
 defaultExportSettings :: ExportSettings
 defaultExportSettings = ExportSettings
   { exportSubSuperscripts = True
+  , exportDrawers = Left ["LOGBOOK"]
   }
 
 
@@ -163,9 +169,16 @@ defaultExportSettings = ExportSettings
 --
 type ExportSettingSetter a = a -> ExportSettings -> ExportSettings
 
+-- | Set export options for sub/superscript parsing.  The short syntax will
+-- not be parsed if this is set set to @False@.
 setExportSubSuperscripts :: ExportSettingSetter Bool
 setExportSubSuperscripts val es = es { exportSubSuperscripts = val }
 
+-- | Set export options for drawers.  See the @exportDrawers@ in ADT
+-- @ExportSettings@ for details.
+setExportDrawers :: ExportSettingSetter (Either [String] [String])
+setExportDrawers val es = es { exportDrawers = val }
+
 -- | Modify a parser state
 modifyExportSettings :: ExportSettingSetter a -> a -> OrgParserState -> OrgParserState
 modifyExportSettings setter val state =

tests/Tests/Readers/Org.hs

@@ -420,9 +420,10 @@ tests =
 
       , "Drawers can be arbitrary" =:
           unlines [ ":FOO:"
+                  , "/bar/"
                   , ":END:"
                   ] =?>
-          (mempty::Blocks)
+          divWith (mempty, ["FOO", "drawer"], mempty) (para $ emph "bar")
 
       , "Anchor reference" =:
           unlines [ "<<link-here>> Target."
@@ -475,6 +476,28 @@ tests =
                   , "a^b"
                   ] =?>
           para "a^b"
+
+      , "Export option: directly select drawers to be exported" =:
+          unlines [ "#+OPTIONS: d:(\"IMPORTANT\")"
+                  , ":IMPORTANT:"
+                  , "23"
+                  , ":END:"
+                  , ":BORING:"
+                  , "very boring"
+                  , ":END:"
+                  ] =?>
+          divWith (mempty, ["IMPORTANT", "drawer"], mempty) (para "23")
+
+      , "Export option: exclude drawers from being exported" =:
+          unlines [ "#+OPTIONS: d:(not \"BORING\")"
+                  , ":IMPORTANT:"
+                  , "5"
+                  , ":END:"
+                  , ":BORING:"
+                  , "very boring"
+                  , ":END:"
+                  ] =?>
+          divWith (mempty, ["IMPORTANT", "drawer"], mempty) (para "5")
       ]
 
   , testGroup "Basic Blocks" $