Fix readWithM with Stream.

pandoc.cabal

@@ -394,8 +394,7 @@ library
                  http-types >= 0.8 && < 0.13,
                  case-insensitive >= 1.2 && < 1.3,
                  unicode-transforms >= 0.3 && < 0.4,
-                 HsYAML >= 0.1.1.1 && < 0.2,
-                 monad-loops >= 0.4 && < 0.5
+                 HsYAML >= 0.1.1.1 && < 0.2
   if impl(ghc < 8.0)
     build-depends: semigroups == 0.18.*,
                    -- basement 0.0.8 and foundation 0.0.21, transitive

src/Text/Pandoc/Parsing.hs

@@ -198,7 +198,6 @@ where
 
 import Prelude
 import Control.Monad.Identity
-import Control.Monad.Loops (unfoldM)
 import Control.Monad.Reader
 import Data.Char (chr, isAlphaNum, isAscii, isAsciiUpper,
                   isPunctuation, isSpace, ord, toLower, toUpper)
@@ -222,7 +221,6 @@ import Text.Pandoc.Shared
 import qualified Text.Pandoc.UTF8 as UTF8 (putStrLn)
 import Text.Pandoc.XML (fromEntities)
 import Text.Parsec hiding (token)
-import qualified Text.Parsec (uncons)
 import Text.Parsec.Pos (initialPos, newPos, updatePosString)
 
 import Control.Monad.Except
@@ -1056,10 +1054,10 @@ readWithM parser state input = do
   case res of
     Right x -> return $ Right x
     Left e  -> do
-      inp <- map fst <$> unfoldM (Text.Parsec.uncons input)
+      inp <- either (const "") id
+             <$> runParserT (many1 anyChar) state "source" input
       return $ Left $ PandocParsecError inp e
 
-
 -- | Parse a string with a given parser and state
 readWith :: Parser [Char] st a
          -> st

src/Text/Pandoc/Readers/Roff.hs

@@ -53,7 +53,7 @@ import Prelude
 import Safe (lastDef)
 import Control.Monad (void, mzero, mplus, guard)
 import Control.Monad.Except (throwError)
-import Control.Monad.State.Strict (StateT(..), evalStateT, get, modify, put)
+import Control.Monad.State (StateT(..), evalStateT, get, modify, put)
 import Text.Pandoc.Class
        (getResourcePath, readFileFromDirs, PandocMonad(..), report)
 import Data.Char (isLower, toLower, toUpper, chr,