Module readline

Here is my simple script on readline.

import readline
import os

def completer(text,state):
    ds=os.listdir()
    rs=list(filter(lambda s:s.startswith(text),ds))
    if state<len(rs):
        return rs[state]
    return None
readline.parse_and_bind("tab: complete")
readline.set_completer(completer)
input()

• 必须注意如果在函数中有错误的话，在你按下tab键后什么都不会发生（新手会在这里卡壳）。要知道，readline非常高级地封装了你的函数，这样才能在input中补全。但这对debug来说不见得是一件好事。较好的方法是先调用一下你的函数completer('c',0)并检查输出，这样函数中的Exception会正常raise。

• 形象理解的话，state其实就是第几选项的序号。

• Expecially notice that if there's any exception raised in your script, nothing would happen when you pressed .The best way I thought of is to call completer('c',0) first and check the return value when debugging.

• As for the parameter state , it's just a index of the options.