6.7. `readline` — GNU readline 接口 ¶

The readline 模块定义了促进 Python 解释器补全和读取/写入历史文件的很多函数。可以直接使用此模块，或凭借 rlcompleter 模块，支持交互提示补全 Python 标识符。使用此模块做出的设置会影响解释器交互提示的行为和提供提示通过内置 input() 函数。

注意

可以实现底层 readline 库 API 通过 libedit library instead of GNU readline. On MacOS X the readline 模块检测运行时在使用哪个库。

配置文件对于 libedit 异于 GNU readline。若以编程方式加载配置字符串，可以校验文本 libedit 在 readline.__doc__ 以区分 GNU readline 和 libedit。

可以凭借初始化文件配置 readline 键绑定，通常 .inputrc 在您的 Home (主) 目录。见 readline 初始文件在 GNU readline 手册了解该文件的格式和可允许构造的有关信息，及 readline 库的一般能力。

6.7.1. 初始文件 ¶

下列函数涉及初始文件和用户配置：

readline. parse_and_bind ( string ) ¶

readline. read_init_file ( [ filename ] ) ¶

6.7.2. 行缓冲 ¶

下列函数运转于行缓冲:

readline. get_line_buffer ( ) ¶

readline. insert_text ( string ) ¶

readline. redisplay ( ) ¶

6.7.3. 历史文件 ¶

下列函数运转于历史文件:

readline. read_history_file ( [ filename ] ) ¶

readline. write_history_file ( [ filename ] ) ¶

readline. append_history_file ( nelements [ , filename ] ) ¶

readline. get_history_length ( ) ¶
readline. set_history_length ( length ) ¶

6.7.4. 历史列表 ¶

下列函数运转于全局历史列表:

readline. clear_history ( ) ¶

readline. get_current_history_length ( ) ¶

readline. get_history_item ( index ) ¶

readline. remove_history_item ( pos ) ¶

readline. replace_history_item ( pos , line ) ¶

readline. add_history ( line ) ¶

6.7.5. 启动挂钩 ¶

readline. set_startup_hook ( [ function ] ) ¶

readline. set_pre_input_hook ( [ function ] ) ¶

6.7.6. 补全 ¶

The following functions relate to implementing a custom word completion function. This is typically operated by the Tab key, and can suggest and automatically complete a word being typed. By default, Readline is set up to be used by rlcompleter to complete Python identifiers for the interactive interpreter. If the readline module is to be used with a custom completer, a different set of word delimiters should be set.

readline. set_completer ( [ function ] ) ¶

readline. get_completer ( ) ¶

readline. get_completion_type ( ) ¶

readline. get_begidx ( ) ¶
readline. get_endidx ( ) ¶

readline. set_completer_delims ( string ) ¶
readline. get_completer_delims ( ) ¶

readline. set_completion_display_matches_hook ( [ function ] ) ¶

6.7.7. 范例 ¶

以下范例演示如何使用 readline 模块的历史读取和写入功能，以自动加载和保存历史文件命名 .python_history 从用户 Home (主) 目录。以下代码在交互式会话期间，通常会自动执行从用户的 PYTHONSTARTUP 文件。

import atexit
import os
import readline
histfile = os.path.join(os.path.expanduser("~"), ".python_history")
try:
    readline.read_history_file(histfile)
    # default history len is -1 (infinite), which may grow unruly
    readline.set_history_length(1000)
except FileNotFoundError:
    pass
atexit.register(readline.write_history_file, histfile)

此代码实际会自动运行，当 Python 运行在交互模式 (见 readline 配置 ).

以下范例达成相同目标但支持并发交互会话，通过只追加新历史。

import atexit
import os
import readline
histfile = os.path.join(os.path.expanduser("~"), ".python_history")
try:
    readline.read_history_file(histfile)
    h_len = readline.get_history_length()
except FileNotFoundError:
    open(histfile, 'wb').close()
    h_len = 0
def save(prev_h_len, histfile):
    new_h_len = readline.get_history_length()
    readline.set_history_length(1000)
    readline.append_history_file(new_h_len - prev_h_len, histfile)
atexit.register(save, h_len, histfile)

以下范例扩展了 code.InteractiveConsole 类以支持历史的保存/还原。

import atexit
import code
import os
import readline
class HistoryConsole(code.InteractiveConsole):
    def __init__(self, locals=None, filename="<console>",
                 histfile=os.path.expanduser("~/.console-history")):
        code.InteractiveConsole.__init__(self, locals, filename)
        self.init_history(histfile)
    def init_history(self, histfile):
        readline.parse_and_bind("tab: complete")
        if hasattr(readline, "read_history_file"):
            try:
                readline.read_history_file(histfile)
            except FileNotFoundError:
                pass
            atexit.register(self.save_history, histfile)
    def save_history(self, histfile):
        readline.set_history_length(1000)
        readline.write_history_file(histfile)

6.7. readline — GNU readline 接口 ¶