setMode :: CmdLineMode -> String -> ModeM ()
setMode m flag = do
(old_mode, old_flag, flags) <- getCmdLineState
- when (notNull old_flag && flag /= old_flag) $
- throwDyn (UsageError
- ("cannot use `" ++ old_flag ++ "' with `" ++ flag ++ "'"))
- putCmdLineState (m, flag, flags)
+ if notNull old_flag && flag /= old_flag
+ then throwDyn (UsageError
+ ("cannot use `" ++ old_flag ++ "' with `" ++ flag ++ "'"))
+ else putCmdLineState (m, flag, flags)
addFlag :: String -> ModeM ()
addFlag s = do