Muse reader: parse verse markup (#3882)

src/Text/Pandoc/Readers/Muse.hs

@@ -32,7 +32,6 @@ TODO:
 - {{{ }}} syntax for <example>
 - Page breaks (five "*")
 - Headings with anchors (make it round trip with Muse writer)
-- Verse markup (">")
 - Org tables
 - table.el tables
 - Images with attributes (floating and width)
@@ -181,6 +180,7 @@ blockElements = choice [ comment
                        , rightTag
                        , quoteTag
                        , verseTag
+                       , lineBlock
                        , bulletList
                        , orderedList
                        , definitionList
@@ -298,6 +298,26 @@ noteBlock = try $ do
     blocksTillNote =
       many1Till block (eof <|> () <$ lookAhead noteMarker)
 
+--
+-- Verse markup
+--
+
+lineVerseLine :: PandocMonad m => MuseParser m String
+lineVerseLine = try $ do
+  char '>'
+  white <- many1 (char ' ' >> pure '\160')
+  rest <- anyLine
+  return $ tail white ++ rest
+
+blanklineVerseLine :: PandocMonad m => MuseParser m Char
+blanklineVerseLine = try $ char '>' >> blankline
+
+lineBlock :: PandocMonad m => MuseParser m (F Blocks)
+lineBlock = try $ do
+  lns <- many1 (pure <$> blanklineVerseLine <|> lineVerseLine)
+  lns' <- mapM (parseFromString' (trimInlinesF . mconcat <$> many inline)) lns
+  return $ B.lineBlock <$> sequence lns'
+
 --
 -- lists
 --

test/Tests/Readers/Muse.hs

@@ -145,6 +145,30 @@ tests =
                     , "  with a continuation"
                     ] =?>
           blockQuote (para "This is a quotation with a continuation")
+        , "Verse" =:
+          T.unlines [ "> This is"
+                    , "> First stanza"
+                    , ">" -- Emacs produces verbatim ">" here, we follow Amusewiki
+                    , "> And this is"
+                    , ">   Second stanza"
+                    , ">"
+                    , ""
+                    , ">"
+                    , ""
+                    , "> Another verse"
+                    , ">    is here"
+                    ] =?>
+          lineBlock [ "This is"
+                    , "First stanza"
+                    , ""
+                    , "And this is"
+                    , "\160\160Second stanza"
+                    , ""
+                    ] <>
+          lineBlock [ "" ] <>
+          lineBlock [ "Another verse"
+                    , "\160\160\160is here"
+                    ]
         ]
       , "Quote tag" =: "<quote>Hello, world</quote>" =?> blockQuote (para $ text "Hello, world")
       , "Verse tag" =: