Muse reader: parse <verse> tag (#3872)

src/Text/Pandoc/Readers/Muse.hs

@@ -32,7 +32,7 @@ TODO:
 - {{{ }}} syntax for <example>
 - Page breaks (five "*")
 - Headings with anchors (make it round trip with Muse writer)
-- <verse> and ">"
+- Verse markup (">")
 - Org tables
 - table.el tables
 - Images with attributes (floating and width)
@@ -180,6 +180,7 @@ blockElements = choice [ comment
                        , centerTag
                        , rightTag
                        , quoteTag
+                       , verseTag
                        , bulletList
                        , orderedList
                        , definitionList
@@ -244,6 +245,25 @@ rightTag = blockTag id "right"
 quoteTag :: PandocMonad m => MuseParser m (F Blocks)
 quoteTag = withQuoteContext InDoubleQuote $ blockTag B.blockQuote "quote"
 
+verseLine :: PandocMonad m => MuseParser m String
+verseLine = do
+  line <- anyLine <|> many1Till anyChar eof
+  let (white, rest) = span (== ' ') line
+  return $ replicate (length white) '\160' ++ rest
+
+verseLines :: PandocMonad m => MuseParser m (F Blocks)
+verseLines = do
+  optionMaybe blankline -- Skip blankline after opening tag on separate line
+  lns <- many verseLine
+  lns' <- mapM (parseFromString' (trimInlinesF . mconcat <$> many inline)) lns
+  return $ B.lineBlock <$> sequence lns'
+
+verseTag :: PandocMonad m => MuseParser m (F Blocks)
+verseTag = do
+  (_, content) <- htmlElement "verse"
+  parsedContent <- parseFromString verseLines content
+  return parsedContent
+
 commentTag :: PandocMonad m => MuseParser m (F Blocks)
 commentTag = parseHtmlContent "comment" anyChar >> return mempty
 

test/Tests/Readers/Muse.hs

@@ -147,6 +147,27 @@ tests =
           blockQuote (para "This is a quotation with a continuation")
         ]
       , "Quote tag" =: "<quote>Hello, world</quote>" =?> blockQuote (para $ text "Hello, world")
+      , "Verse tag" =:
+        T.unlines [ "<verse>"
+                  , ""
+                  , "Foo bar baz"
+                  , "  One two three"
+                  , ""
+                  , "</verse>"
+                  , "<verse>Foo bar</verse>"
+                  , "<verse>"
+                  , "Foo bar</verse>"
+                  , "<verse>"
+                  , "   Foo</verse>"
+                  ] =?>
+        lineBlock [ ""
+                  , text "Foo bar baz"
+                  , text "\160\160One two three"
+                  , ""
+                  ] <>
+        lineBlock [ "Foo bar" ] <>
+        lineBlock [ "Foo bar" ] <>
+        lineBlock [ "\160\160\160Foo" ]
       , "Center" =: "<center>Hello, world</center>" =?> para (text "Hello, world")
       , "Right" =: "<right>Hello, world</right>" =?> para (text "Hello, world")
       , testGroup "Comments"