-- | Parse an expression using appropriate local context.
parseExpression :: Maybe (String,String)
                -> KateParser Token
parseExpression mbcontext = do
  (lang,cont) <- maybe currentContext return mbcontext
  result <- parseRules (lang,cont)
  optional $ do eof
                updateState $ \st -> st{ synStPrevChar = '\n' }
                pEndLine
  return result
parseExpression :: Maybe (String,String)
                -> KateParser Token
parseExpression mbcontext = do
  (lang,cont) <- maybe currentContext return mbcontext
  result <- parseRules (lang,cont)
  optional $ do eof
                updateState $ \st -> st{ synStPrevChar = '\n' }
                pEndLine
  return result
parseExpression mbcontext = do
  (lang,cont) <- maybe currentContext return mbcontext
  result <- parseRules (lang,cont)
  optional $ do eof
                updateState $ \st -> st{ synStPrevChar = '\n' }
                pEndLine
  return result