Function register_readline

Lib/site.py:495–593

Configure readline completion on interactive prompts. If the readline module can be imported, the hook will set the Tab key as completion key and register ~/.python_history as history file. This can be overridden in the sitecustomize or usercustomize module, or in a PYTHONSTARTUP fi

()

def register_readline():
    """Configure readline completion on interactive prompts.

    If the readline module can be imported, the hook will set the Tab key
    as completion key and register ~/.python_history as history file.
    This can be overridden in the sitecustomize or usercustomize module,
    or in a PYTHONSTARTUP file.
    """
    if not sys.flags.ignore_environment:
        PYTHON_BASIC_REPL = os.getenv("PYTHON_BASIC_REPL")
    else:
        PYTHON_BASIC_REPL = False

    import atexit

    try:
        try:
            import readline
        except ImportError:
            readline = None
        else:
            import rlcompleter  # noqa: F401
    except ImportError:
        return

    try:
        if PYTHON_BASIC_REPL:
            CAN_USE_PYREPL = False
        else:
            original_path = sys.path
            sys.path = [p for p in original_path if p != '']
            try:
                import _pyrepl.readline
                if os.name == "nt":
                    import _pyrepl.windows_console
                    console_errors = (_pyrepl.windows_console._error,)
                else:
                    import _pyrepl.unix_console
                    console_errors = _pyrepl.unix_console._error
                from _pyrepl.main import CAN_USE_PYREPL
            finally:
                sys.path = original_path
    except ImportError:
        return

    if readline is not None:
        # Reading the initialization (config) file may not be enough to set a
        # completion key, so we set one first and then read the file.
        if readline.backend == 'editline':
            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