-- | Add a completer to an argument.
--
-- A completer is a function String -> IO String which, given a partial
-- argument, returns all possible completions for that argument.
completer :: HasCompleter f => Completer -> Mod f a
completer f = fieldMod $ modCompleter (`mappend` f)
completer :: HasCompleter f => Completer -> Mod f a
completer f = fieldMod $ modCompleter (`mappend` f)
completer f = fieldMod $ modCompleter (`mappend` f)