Python readline 模块，set_pre_input_hook() 实例源码

def init_completer(self):
        readline.set_pre_input_hook(self.pre_input_hook)
        readline.set_completer_delims(" \t")

def init_readline(self):
        """Activates history and tab completion
        """
        # - mainly borrowed from site.enablerlcompleter() from py3.4+

        # Reading the initialization (config) file may not be enough to set a
        # completion key, so we set one first and then read the file.
        readline_doc = getattr(readline, '__doc__', '')
        if readline_doc is not None and 'libedit' in readline_doc:
            readline.parse_and_bind('bind ^I rl_complete')
        else:
            readline.parse_and_bind('tab: complete')

        try:
            readline.read_init_file()
        except OSError:
            # An OSError here could have many causes, but the most likely one
            # is that there's no .inputrc file (or .editrc file in the case of
            # Mac OS X + libedit) in the expected location.  In that case, we
            # want to ignore the exception.
            pass

        if readline.get_current_history_length() == 0:
            # If no history was loaded, default to .python_history.
            # The guard is necessary to avoid doubling history size at
            # each interpreter exit when readline was already configured
            # see: http://bugs.python.org/issue5845#msg198636
            try:
                readline.read_history_file(config['HISTFILE'])
            except IOError:
                pass
            atexit.register(readline.write_history_file,
                            config['HISTFILE'])
        readline.set_history_length(config['HISTSIZE'])

        # - replace default completer
        readline.set_completer(self.improved_rlcompleter())

        # - enable auto-indenting
        readline.set_pre_input_hook(self.auto_indent_hook)

def init_completer(self):
        readline.set_pre_input_hook(self.pre_input_hook)
        readline.set_completer_delims(" \t")

def default_input(prompt, default=None):
    # https://chistera.yi.org/~dato/blog/entries/2008/02/14/python_raw_input_with_an_editable_default_value_using_readline.html
    if not default:
        default = ""

    def pre_input_hook():
        readline.insert_text(default)
        readline.redisplay()

    prompt += ": "
    readline.set_pre_input_hook(pre_input_hook)
    try:
        return raw_input(prompt)
    finally:
        readline.set_pre_input_hook(None)

def postcmd(self, stop, line):
        """Called just before execution of line. For readline, this handles the
        automatic indentation of code blocks.
        """
        try:
            import readline
        except ImportError:
            return stop
        if self.need_more_lines:
            if len(line.strip()) == 0:
                readline.set_pre_input_hook(None)
                self._current_indent = ''
            elif line.rstrip()[-1] == ':':
                ind = line[:len(line) - len(line.lstrip())]
                ind += builtins.__xonsh_env__.get('INDENT')
                readline.set_pre_input_hook(_insert_text_func(ind, readline))
                self._current_indent = ind
            elif line.split(maxsplit=1)[0] in DEDENT_TOKENS:
                env = builtins.__xonsh_env__
                ind = self._current_indent[:-len(env.get('INDENT'))]
                readline.set_pre_input_hook(_insert_text_func(ind, readline))
                self._current_indent = ind
            else:
                ind = line[:len(line) - len(line.lstrip())]
                if ind != self._current_indent:
                    insert_func = _insert_text_func(ind, readline)
                    readline.set_pre_input_hook(insert_func)
                    self._current_indent = ind
        else:
            readline.set_pre_input_hook(None)
        return stop