PDF: Better error message.

src/Text/Pandoc/PDF.hs

@@ -56,10 +56,11 @@ tex2pdf' :: FilePath                        -- ^ temp directory for output
          -> IO (Either ByteString ByteString)
 tex2pdf' tmpDir program source = do
   (exit, log', mbPdf) <- runTeXProgram program 3 tmpDir source
+  let msg = "Error producing PDF from TeX source."
   case (exit, mbPdf) of
-       (ExitFailure _, _)      -> return $ Left $ extractMsg log'
-       (ExitSuccess, Nothing)  -> return $ Left
-                                   "tex2pdf: ExitSuccess but no PDF created!"
+       (ExitFailure _, _)      -> return $ Left $
+                                     msg <> "\n" <> extractMsg log'
+       (ExitSuccess, Nothing)  -> return $ Left msg
        (ExitSuccess, Just pdf) -> return $ Right pdf
 
 data TeXProgram = PDFLaTeX
@@ -70,6 +71,9 @@ data TeXProgram = PDFLaTeX
                 | PDFTeX
                 deriving (Show, Read)
 
+(<>) :: ByteString -> ByteString -> ByteString
+(<>) = B.append
+
 -- parsing output
 
 extractMsg :: ByteString -> ByteString

src/pandoc.hs

@@ -975,10 +975,9 @@ main = do
            do res <- tex2pdf PDFLaTeX $ writeLaTeX writerOptions doc2
               case res of
                    Right pdf -> writeBinary pdf
-                   Left err' -> B.hPutStr stderr err' >> B.hPutStr stderr nl
+                   Left err' -> B.hPutStr stderr err'
                 | otherwise -> error $ "Unknown writer: " ++ writerName'
           where writeBinary  = B.writeFile (encodeString outputFile)
-                nl           = B.singleton 10
         Just r  -> writerFn outputFile =<< postProcess result
           where writerFn "-" = UTF8.putStr
                 writerFn f   = UTF8.writeFile f