Muse reader: parse <verse> tag in one pass

instead of using parseFromString.

This change makes it possible to have verbatim </verse> tag
inside verse.

src/Text/Pandoc/Readers/Muse.hs

@@ -462,16 +462,19 @@ verseLine = do
   rest <- manyTill (choice inlineList) newline
   return $ trimInlinesF $ mconcat (pure indent : rest)
 
-verseLines :: PandocMonad m => MuseParser m (F Blocks)
-verseLines = do
-  lns <- many verseLine
-  return $ B.lineBlock <$> sequence lns
-
 -- | Parse @\<verse>@ tag.
 verseTag :: PandocMonad m => MuseParser m (F Blocks)
-verseTag = do
-  (_, content) <- htmlBlock "verse"
-  parseFromString verseLines (intercalate "\n" $ dropSpacePrefix $ splitOn "\n" $ lchop content)
+verseTag = try $ do
+  many spaceChar
+  pos <- getPosition
+  (TagOpen _ _, _) <- htmlTag (~== TagOpen "verse" [])
+  manyTill spaceChar eol
+  let indent = count (sourceColumn pos - 1) spaceChar
+  content <- sequence <$> manyTill (indent >> verseLine) (try $ indent >> endtag)
+  manyTill spaceChar eol
+  return $ B.lineBlock <$> content
+  where
+    endtag = void $ htmlTag (~== TagClose "verse")
 
 -- | Parse @\<comment>@ tag.
 commentTag :: PandocMonad m => MuseParser m (F Blocks)

test/Tests/Readers/Muse.hs

@@ -407,6 +407,12 @@ tests =
                   , "</verse>"
                   ] =?>
         lineBlock [ "" ]
+      , "Verse tag with verbatim close tag inside" =:
+        T.unlines [ "<verse>"
+                  , "<verbatim></verse></verbatim>"
+                  , "</verse>"
+                  ] =?>
+        lineBlock [ "</verse>" ]
       , testGroup "Example"
         [ "Braces on separate lines" =:
           T.unlines [ "{{{"