def restore_old_history(self):
     readline.clear_history()
     for line in self._oldHistory:
         if line is None:
             continue
         readline.add_history(line)
     self._oldHistory = []

    def append(self, event):
        """
        Append a new history event.

        :param str event: event to append
        """
        readline.add_history(event)

 def run(self):
     try:
         import readline
     except ImportError:
         return
     hist = builtins.__xonsh_history__
     while self.wait_for_gc and hist.gc.is_alive():
         time.sleep(0.011)  # gc sleeps for 0.01 secs, sleep a beat longer
     files = hist.gc.files()
     i = 1
     for _, _, f in files:
         try:
             lj = LazyJSON(f, reopen=False)
             for command in lj['cmds']:
                 inp = command['inp'].splitlines()
                 for line in inp:
                     if line == 'EOF':
                         continue
                     readline.add_history(line)
                     if RL_LIB is not None:
                         RL_LIB.history_set_pos(i)
                     i += 1
             lj.close()
         except (IOError, OSError, ValueError):
             continue

    def set_context(self, name):
        """Set the current history context.

        This swaps in a new history context by loading
        the history from the contexts filename.  The
        old context's history is saved first.
        """

        if name not in self.contexts:
            raise ValueError("Invalid history context: %s" % name)

        if self.current:
            if name == self.current.name:
                return
            self.save()

        self.current = self.contexts[name]

        try:
            readline.clear_history()
            if self.current.obj:
                with open(self.current.filename, "r") as f:
                    lines = pickle.load(f)

                for line in lines:
                    readline.add_history(line)

            else:
                readline.read_history_file(self.current.filename)
        except IOError:
            pass

    def getInput(self):
        out = None
        if self._default == None:
            self._default = datetime.datetime.now(dateutil.tz.tzlocal())
        readline.clear_history()

        # put the default value into history
        readline.add_history(self._formatDate(self._default))

        # try to complete during typing.
        readline.set_completer_delims('\n;')
        readline.parse_and_bind("tab: complete")
        readline.set_completer(self.comp)

        # get user input until it's acceptable
        while out == None:
            inp = input(self._display + " [{}]: "
                        .format(self._formatDate(self._default)))
            if inp == "?":
                self.printSpec()
            else:
                try:
                    out = self.tryParse(inp.strip(), self._default)
                except Exception as e:
                    # although the value is not acceptable, give user
                    # a chance to modify it.
                    hist = inp.strip()
                    if len(hist) > 0:
                        readline.add_history(inp.strip())
                    self.printSpec()

        readline.clear_history()
        readline.set_completer()
        # print(">> {}: {}".format(self._display, out.strftime("%Y/%m/%d %H:%M")))
        return out

    def _run(self):
        """Go through all commands on a pseudo-shell, and execute them,
        caching the passphrase at some point."""
        
        print "Welcome to SFLvault. Type 'help' for help."
        prompt = "SFLvault> "
        
        while True:
            cmd = raw_input(prompt)
            if not cmd:
                continue
            
            # Get sys.argv-like parameters
            args = shlex.split(cmd)

            # Local (shell) cmds take precedence over SFLvaultCommand cmds.
            if len(args) and hasattr(self, args[0]):
                getattr(self, args[0])()
            else:
                parser = NoExitParser(usage=optparse.SUPPRESS_USAGE)
                runcmd = SFLvaultCommand(self.config, self.vault, parser)
                try:
                    runcmd._run(args)
                except ExitParserException, e:
                    pass
                
                if hasattr(runcmd, 'next_command') \
                          and platform.system() != 'Windows':
                    print "[Added to shell history: %s]" % runcmd.next_command
                    readline.add_history(runcmd.next_command)

    def edit_track(self, files):
        input = raw_input('[A]ccept, 1-%d to edit name, s/pattern/repl/g: ' % len(files))

        try:
            filename = files.keys()[int(input) - 1]
            old_name = files[filename]

            readline.add_history(old_name)
            new_name = raw_input('New name [%s] (press up): ' % old_name)

            files[filename] = new_name or old_name
        except (ValueError, IndexError):
            if input.upper() in ('', 'Y'):
                return True

        if input.startswith('s/'):
            elems = [re.escape(x) for x in input.split('/')]
            if len(elems) != 4:
                print "W: Malformed regular expression"
                return False

            count = 0
            for filename, name in files.iteritems():
                new_name = re.sub(elems[1], elems[2], name)
                if name != new_name:
                    files[filename] = new_name
                    count += 1
            print "I: %d track(s) changed" % count

        return False

    def input_callback(self, prompt, completions=True):
        # Setup subedit
        self.curs_set(1)

        self.callbacks["set_var"]("input_do_completions", completions)
        self.callbacks["set_var"]("input_prompt", prompt)

        self.input_box.reset()
        self.input_box.refresh()
        curses.doupdate()

        self.pseudo_input_box.keypad(0)

        r = raw_readline()
        if not r:
            r = ""

        self.pseudo_input_box.keypad(1)

        # Only add history for commands, not other prompts
        if completions:
            readline.add_history(r)

        self.callbacks["set_var"]("input_prompt", "")
        self.input_box.reset()
        self.input_box.refresh()
        curses.doupdate()

        self.curs_set(0)
        return r

def exec_cmd(cmdline):
    """Interpret a command."""
    cmd, arg = _parse_cmdline(cmdline)
    if not cmd:
        print('Bad command.')
    else:
        cmd_callable = get_cmd(cmd)
        if not cmd:
            print('Type a command. Try \'help\'.')
        elif cmd_callable:
            try:
                cmd_callable(arg)
            except ImproperArgError as e:
                print(str(e))
            except UsageError as e:
                print('usage: ' + cmd + ' ' + str(e))
            except MissingDeckError:
                print('No active deck. Create a new deck with the \'deck\' '
                      'command.')
            except cards.ScrapeError as e:
                print('Scrape failed: ' + str(e))
            if 'readline' in sys.modules:
                readline.add_history(cmdline)
        else:
            print('%s is not a command. Try \'help\'.' % str(cmd))
    return True

    def _read_file(self, fname):
        """
        Generator to read ScriptLine objects from the file named
        `fname`.
        """

        lno = 0
        # Ignore leading blank lines that would be treated as pauses
        inhibit_pause = True
        with open(fname, 'r') as f:
            for line in f:
                # Track the line number
                lno += 1

                # Parse the line
                sc_line = ScriptLine(fname, lno, line)

                # Process pauses
                if sc_line.type == 'pause':
                    if inhibit_pause:
                        # Apply pause inhibition
                        continue

                    # Inhibit future pausing
                    inhibit_pause = True
                else:
                    # Not inhibiting any more pauses
                    inhibit_pause = False

                # Add the line to the history
                readline.add_history(sc_line.raw)

                # Yield the line
                yield sc_line

 def _add_line_to_history(self, line):
     """Adds the given line to readline history, only if the line
     is non-empty. If the line starts with a prompt symbol, the
     prompt is stripped from the line.
     """
     if line and HAS_READLINE:
         readline.add_history(line)

    def multiline(self, firstline=''):
        full_input = []
        # keep a list of the entries that we've made in history
        old_hist = []
        if firstline:
            print '  ' + firstline
            full_input.append(firstline)
        while True:
            if hasReadline:
                # add the current readline position
                old_hist.append(readline.get_current_history_length())
            if self.use_rawinput:
                try:
                    line = raw_input(self.multiline_prompt)
                except EOFError:
                    line = 'EOF'
            else:
                self.stdout.write(self.multiline_prompt)
                self.stdout.flush()
                line = self.stdin.readline()
                if not len(line):
                    line = 'EOF'
                else:
                    line = line[:-1] # chop \n
            if line == 'EOF':
                break
            full_input.append(line)

        # add the final readline history position
        if hasReadline:
            old_hist.append(readline.get_current_history_length())

        cmd = '\n'.join(full_input) + '\n'

        if hasReadline:
            # remove the old, individual readline history entries.

            # first remove any duplicate entries
            old_hist = sorted(set(old_hist))

            # Make sure you do this in reversed order so you move from
            # the end of the history up.
            for pos in reversed(old_hist):
                # get_current_history_length returns pos + 1
                readline.remove_history_item(pos - 1)
            # now add the full line
            readline.add_history(cmd)

        locals = self.curframe.f_locals
        globals = self.curframe.f_globals
        print
        self.save_history()
        try:
            try:
                code = compile(cmd, '<stdin>', 'single')
                exec code in globals, locals
            except:
                print self._reprExc()
        finally:
            self.read_history()

        def _process_input(self):
            if sys.version_info[0] >= 3:
                input_impl = input
            else:
                input_impl = raw_input
            while True:
                self._idle.wait()
                expression = ""
                line = ""
                while len(expression) == 0 or line.endswith("\\"):
                    try:
                        if len(expression) == 0:
                            line = input_impl(">>> ")
                        else:
                            line = input_impl("... ")
                    except EOFError:
                        return
                    if len(line.strip()) > 0:
                        if len(expression) > 0:
                            expression += "\n"
                        expression += line.rstrip("\\")

                if HAVE_READLINE:
                    readline.add_history(expression)
                self._idle.clear()
                self._reactor.schedule(lambda: self._send_expression(expression))

    def loop(self):
        """
        Starts the command loop

        loop() -> None
        """

        # Process commands
        # NOTE: doesn't work with ; inside quoted arguments
        cmds = [arg.strip() for arg in self._args.command.split(';')] if self._args.command else []

        self._entry()

        while True:
            self._preInput()

            try:
                if len(cmds):
                    res = cmds.pop(0)
                    print(">>> " + res)
                    readline.add_history(res)
                else:
                    res = input('>>> ').strip()
            except EOFError:
                print(colored("(EOF)", 'yellow'))
                break

            self.runCommandRaw(res)
            self._postInput()

        self._exit()

    def input(self, prompt=None, *, history=True):
        """Read a single line

        Parameters
        ----------
        history: bool, optional
            append read line to history (only if ``stdin`` is ``None``) (defaults to ``True``)

        Returns
        -------
        str
            the read line
        """
        if prompt is None:
            prompt = self.__prompt
        if self.__stdin is not None:
            try:
                line = next(self.__stdin)
                if readline_module:
                    readline_module.add_history(line.rstrip('\n'))
                return line
            except StopIteration:
                return None
        else:
            return input_function(prompt=prompt, history=history)  # pylint: disable=bad-builtin

    def append(self, event):
        '''
        Append a new history event.

        :param str event: event to append
        '''
        readline.add_history(event)

    def wrapper(*args, **kwargs):
        try:
            import readline
            handle_readline = True
        except ImportError:
            handle_readline = False

        if handle_readline:
            # backup & reset readline completer
            old_readline_completer = readline.get_completer()
            readline.set_completer((lambda x: x))
            # backup & reset readline history
            old_readline_history = []
            hist_sz = readline.get_current_history_length()
            for i in range(1, hist_sz + 1):
                line = readline.get_history_item(i)
                old_readline_history.append(line)
            readline.clear_history()

        try:
            retval = function(*args, **kwargs)
        finally:

            if handle_readline:
                # restore old readline completer
                readline.set_completer(old_readline_completer)
                # restore old readline history
                readline.clear_history()
                for line in old_readline_history:
                    readline.add_history(line)

        return retval

    def add_item(self, line, force=False):
        # Kludge. pyreadline is a pain in the ass.
        from pyreadline import lineobj
        from pyreadline.unicode_helper import ensure_unicode

        line = ensure_unicode(line.rstrip())
        readline.add_history(lineobj.ReadLineTextBuffer(line))

    def get_meta(prompt, default, default_list):
        default_count = 0
        if default_list:
            if not default:
                count = len(default_list)
                if count == 0:
                    default = ''
                else:
                    if type(default_list[0]) is str:
                        default = default_list[0]
                    else:
                        default = default_list[0][0]
                    default_count = count - 1

            readline.clear_history()
            default_list.reverse()
            for d in default_list:
                if type(d) is str:
                    readline.add_history(d)
                else:
                    readline.add_history(d[0])

        if default_count > 0:
            full_prompt = ('{} [{}](+ {} more): '.
                    format(prompt, default, default_count))
        else:
            full_prompt = ('{} [{}]: '.
                    format(prompt, default))

        result = input(full_prompt)
        if result == '':
            return default
        else:
            return result

def exec_cmd(cmdline):
    """Interpret a command."""
    cmd, arg = _parse_cmdline(cmdline)
    if not cmd:
        print("Bad command.")
    else:
        cmd_callable = get_cmd(cmd)
        if not cmd:
            print("Type a command. Try 'help'.")
        elif cmd_callable:
            try:
                cmd_callable(arg)
            except ImproperArgError as e:
                print(str(e))
            except UsageError as e:
                print("usage: " + cmd + " " + str(e))
            except MissingDeckError:
                print("No active deck. Create a new deck with the 'deck' " "command.")
            except cards.ScrapeError as e:
                print("Scrape failed: " + str(e))
            if "readline" in sys.modules:
                readline.add_history(cmdline)
        else:
            print("%s is not a command. Try 'help'." % str(cmd))
    return True