Org reader: fix paragraph/list interaction

Paragraphs can be followed by lists, even if there is no blank line
between the two blocks.  However, this should only be true if the
paragraph is not within a list, were the preceding block should be
parsed as a plain instead of paragraph (to allow for compact lists).

Thanks to @rgaiacs for bringing this up.

This fixes #2464.

src/Text/Pandoc/Readers/Org.hs

@@ -2,7 +2,7 @@
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
 {-# LANGUAGE MultiParamTypeClasses, FlexibleContexts, FlexibleInstances #-}
 {-
-Copyright (C) 2014-2015 Albert Krewinkel <tarleb@moltkeplatz.de>
+Copyright (C) 2014-2015 Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -24,7 +24,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
    Copyright   : Copyright (C) 2014 Albert Krewinkel
    License     : GNU GPL, version 2 or above
 
-   Maintainer  : Albert Krewinkel <tarleb@moltkeplatz.de>
+   Maintainer  : Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>
 
 Conversion of org-mode formatted plain text to 'Pandoc' document.
 -}
@@ -140,6 +140,7 @@ data OrgParserState = OrgParserState
                       , orgStateMeta                 :: Meta
                       , orgStateMeta'                :: F Meta
                       , orgStateNotes'               :: OrgNoteTable
+                      , orgStateParserContext        :: ParserContext
                       , orgStateIdentifiers          :: [String]
                       , orgStateHeaderMap            :: M.Map Inlines String
                       }
@@ -181,6 +182,7 @@ defaultOrgParserState = OrgParserState
                         , orgStateMeta = nullMeta
                         , orgStateMeta' = return nullMeta
                         , orgStateNotes' = []
+                        , orgStateParserContext = NullState
                         , orgStateIdentifiers = []
                         , orgStateHeaderMap = M.empty
                         }
@@ -291,6 +293,23 @@ blanklines =
        <* updateLastPreCharPos
        <* updateLastForbiddenCharPos
 
+-- | Succeeds when we're in list context.
+inList :: OrgParser ()
+inList = do
+  ctx <- orgStateParserContext <$> getState
+  guard (ctx == ListItemState)
+
+-- | Parse in different context
+withContext :: ParserContext -- ^ New parser context
+            -> OrgParser a   -- ^ Parser to run in that context
+            -> OrgParser a
+withContext context parser = do
+  oldContext <- orgStateParserContext <$> getState
+  updateState $ \s -> s{ orgStateParserContext = context }
+  result <- parser
+  updateState $ \s -> s{ orgStateParserContext = oldContext }
+  return result
+
 --
 -- parsing blocks
 --
@@ -891,9 +910,13 @@ noteBlock = try $ do
 paraOrPlain :: OrgParser (F Blocks)
 paraOrPlain = try $ do
   ils <- parseInlines
-  nl <- option False (newline >> return True)
-  try (guard nl >> notFollowedBy (orderedListStart <|> bulletListStart) >>
-           return (B.para <$> ils))
+  nl <- option False (newline *> return True)
+  -- Read block as paragraph, except if we are in a list context and the block
+  -- is directly followed by a list item, in which case the block is read as
+  -- plain text.
+  try (guard nl
+       *> notFollowedBy (inList *> (orderedListStart <|> bulletListStart))
+       *> return (B.para <$> ils))
     <|>  (return (B.plain <$> ils))
 
 inlinesTillNewline :: OrgParser (F Inlines)
@@ -970,7 +993,7 @@ definitionListItem parseMarkerGetLength = try $ do
 -- parse raw text for one list item, excluding start marker and continuations
 listItem :: OrgParser Int
          -> OrgParser (F Blocks)
-listItem start = try $ do
+listItem start = try . withContext ListItemState $ do
   markerLength <- try start
   firstLine <- anyLineNewline
   blank <- option "" ("\n" <$ blankline)

tests/Tests/Readers/Org.hs

@@ -870,6 +870,14 @@ tests =
                      , para "orange"
                      , para "peach"
                      ]
+
+      , "Recognize preceding paragraphs in non-list contexts" =:
+          unlines [ "CLOSED: [2015-10-19 Mon 15:03]"
+                  , "- Note taken on [2015-10-19 Mon 13:24]"
+                  ] =?>
+          mconcat [ para "CLOSED: [2015-10-19 Mon 15:03]"
+                  , bulletList [ plain "Note taken on [2015-10-19 Mon 13:24]" ]
+                  ]
       ]
 
   , testGroup "Tables"