Org reader: fix inline-LaTeX regression

The last fix for whitespace handling of inline LaTeX commands was
incorrect, preventing correct recognition of inline LaTeX commands which
contain spaces.  This fix ensures that only trailing whitespace is cut
off.

src/Text/Pandoc/Readers/Org.hs

@@ -1581,8 +1581,8 @@ inlineLaTeX = try $ do
 
    parseAsMathMLSym :: String -> Maybe Inlines
    parseAsMathMLSym cs = B.str <$> MathMLEntityMap.getUnicode (clean cs)
-    -- dropWhileEnd would be nice here, but it's not available before base 4.5
-    where clean = reverse . dropWhile (`elem` ("{}" :: String)) . reverse . drop 1
+    -- drop initial backslash and any trailing "{}"
+    where clean = dropWhileEnd (`elem` ("{}" :: String)) . drop 1
 
    state :: ParserState
    state = def{ stateOptions = def{ readerParseRaw = True }}
@@ -1598,13 +1598,18 @@ inlineLaTeXCommand = try $ do
   rest <- getInput
   case runParser rawLaTeXInline def "source" rest of
     Right (RawInline _ cs) -> do
-      -- drop any trailing whitespace, those should not be part of the command
-      let cmdNoSpc = takeWhile (not . isSpace) $ cs
+      -- drop any trailing whitespace, those are not be part of the command as
+      -- far as org mode is concerned.
+      let cmdNoSpc = dropWhileEnd isSpace cs
       let len = length cmdNoSpc
       count len anyChar
       return cmdNoSpc
     _ -> mzero
 
+-- Taken from Data.OldList.
+dropWhileEnd :: (a -> Bool) -> [a] -> [a]
+dropWhileEnd p = foldr (\x xs -> if p x && null xs then [] else x : xs) []
+
 smart :: OrgParser (F Inlines)
 smart = do
   getOption readerSmart >>= guard

tests/Tests/Readers/Org.hs

@@ -308,6 +308,10 @@ tests =
           "\\textit{Emphasised}" =?>
           para (emph "Emphasised")
 
+      , "Inline LaTeX command with spaces" =:
+          "\\emph{Emphasis mine}" =?>
+          para (emph "Emphasis mine")
+
       , "Inline LaTeX math symbol" =:
           "\\tau" =?>
           para (emph "τ")