Python命令行界面中的选项卡完成 - 如何捕获Tab事件

Question

I'm writing a little CLI in Python (as an extension to Mercurial) and would like to support tab-completion. Specifically, I would like catch tabs in the prompt and show a list of matching options (just like bash).

Example: Enter section name:

 ext*TAB*  
 extensions  
 extras

The problem is I'm not sure how to catch the Tab events. I'm using the ui.prompt() API of Mercurial, which is just calling raw_input() under the hood.

As far as I know, raw_input() only returns on 'enter' and if a user enters a tab, the string returned simply includes a "\\t" .

Answer 1

For that you use the readline module.

Simplest code I can think:

import readline
COMMANDS = ['extra', 'extension', 'stuff', 'errors',
            'email', 'foobar', 'foo']

def complete(text, state):
    for cmd in COMMANDS:
        if cmd.startswith(text):
            if not state:
                return cmd
            else:
                state -= 1

readline.parse_and_bind("tab: complete")
readline.set_completer(complete)
raw_input('Enter section name: ')

Example usage:

Enter section name: <tab>
email      errors     extension  extra      foo        foobar    stuff
Enter section name: e<tab>
email      errors     extension  extra      
Enter section name: ext<tab>
extension  extra      

Besides completion, readline provides you with:

• Line editing
• Keybinding configuration (emacs and vi modes included)
• History (up arrow to recall previous values)
• History searching, saving and loading

Answer 2

标准库中作为rlcompleter模块提供了如何与readline一起完成制表完成的一个很好的例子 - 您不能按原样使用它（它基于当前在Python的main和builtin中定义的名称完成），但它显示了如何执行一般任务以及如何将其连接到readline 。

Answer 3

You should almost certainly be using the cmd module , which already implements tab completion and so on, and probably other parts of what you're trying to do, using the readline module and so on. There's no point reinventing the wheel.