1 files changed, 12 insertions, 12 deletions
diff --git a/src/Text/Pandoc/Readers/Muse.hs b/src/Text/Pandoc/Readers/Muse.hs
index 6acc88b3d..3b64fe5ef 100644
--- a/src/Text/Pandoc/Readers/Muse.hs
+++ b/src/Text/Pandoc/Readers/Muse.hs
@@ -45,7 +45,7 @@ import Control.Monad.Reader
 import Control.Monad.Except (throwError)
 import Data.Bifunctor
 import Data.Default
-import Data.List (intercalate)
+import Data.List (intercalate, transpose)
 import Data.List.Split (splitOn)
 import qualified Data.Map as M
 import qualified Data.Set as Set
@@ -135,9 +135,6 @@ parseMuse = do
 
 -- * Utility functions
 
-commonPrefix :: String -> String -> String
-commonPrefix xs ys = map fst $ takeWhile (uncurry (==)) $ zip xs ys
-
 -- | Trim up to one newline from the beginning of the string.
 lchop :: String -> String
 lchop ('\n':xs) = xs
@@ -147,11 +144,14 @@ lchop s = s
 rchop :: String -> String
 rchop = reverse . lchop . reverse
 
+unindent :: String -> String
+unindent = rchop . intercalate "\n" . dropSpacePrefix . splitOn "\n" . lchop
+
 dropSpacePrefix :: [String] -> [String]
-dropSpacePrefix lns =
-  map (drop maxIndent) lns
-  where flns = filter (not . all (== ' ')) lns
-        maxIndent = if null flns then maximum (map length lns) else length $ takeWhile (== ' ') $ foldl1 commonPrefix flns
+dropSpacePrefix lns = drop maxIndent <$> lns
+  where isSpaceChar c = c == ' ' || c == '\t'
+        maxIndent = length $ takeWhile (isSpaceChar . head) $ takeWhile same $ transpose lns
+        same = and . (zipWith (==) <*> drop 1)
 
 atStart :: PandocMonad m => MuseParser m ()
 atStart = do
@@ -380,15 +380,15 @@ amuseHeadingUntil end = try $ do
 example :: PandocMonad m => MuseParser m (F Blocks)
 example = try $ pure . B.codeBlock
   <$  string "{{{"
-  <*  optional blankline
-  <*> manyTill anyChar (try (optional blankline *> string "}}}"))
+  <*  many spaceChar
+  <*> (unindent <$> manyTill anyChar (string "}}}"))
 
 -- | Parse an @\<example>@ tag.
 exampleTag :: PandocMonad m => MuseParser m (F Blocks)
 exampleTag = try $ fmap pure $ B.codeBlockWith
   <$  many spaceChar
   <*> (htmlAttrToPandoc <$> openTag "example")
-  <*> (rchop . intercalate "\n" . dropSpacePrefix . splitOn "\n" . lchop <$> manyTill anyChar (closeTag "example"))
+  <*> (unindent <$> manyTill anyChar (closeTag "example"))
   <*  manyTill spaceChar eol
 
 -- | Parse a @\<literal>@ tag as a raw block.
@@ -398,7 +398,7 @@ literalTag = try $ fmap pure $ B.rawBlock
   <$  many spaceChar
   <*> (fromMaybe "html" . lookup "style" <$> openTag "literal") -- FIXME: Emacs Muse inserts <literal> without style into all output formats, but we assume HTML
   <*  manyTill spaceChar eol
-  <*> (rchop . intercalate "\n" . dropSpacePrefix . splitOn "\n" . lchop <$> manyTill anyChar (closeTag "literal"))
+  <*> (unindent <$> manyTill anyChar (closeTag "literal"))
   <*  manyTill spaceChar eol
 
 -- | Parse @\<center>@ tag.