readline_history.py

#!/usr/bin/env python3
# encoding: utf-8
#
# Copyright (c) 2008 Doug Hellmann All rights reserved.
#
"""
"""


#end_pymotw_header
try:
    import gnureadline as readline
except ImportError:
    import readline
import logging
import os

LOG_FILENAME = '/tmp/completer.log'
HISTORY_FILENAME = '/tmp/completer.hist'

logging.basicConfig(
    format='%(message)s',
    filename=LOG_FILENAME,
    level=logging.DEBUG,
)


def get_history_items():
    num_items = readline.get_current_history_length() + 1
    return [
        readline.get_history_item(i)
        for i in range(1, num_items)
    ]


class HistoryCompleter:

    def __init__(self):
        self.matches = []

    def complete(self, text, state):
        response = None
        if state == 0:
            history_values = get_history_items()
            logging.debug('history: %s', history_values)
            if text:
                self.matches = sorted(
                    h
                    for h in history_values
                    if h and h.startswith(text)
                )
            else:
                self.matches = []
            logging.debug('matches: %s', self.matches)
        try:
            response = self.matches[state]
        except IndexError:
            response = None
        logging.debug('complete(%s, %s) => %s',
                      repr(text), state, repr(response))
        return response


def input_loop():
    if os.path.exists(HISTORY_FILENAME):
        readline.read_history_file(HISTORY_FILENAME)
    print('Max history file length:',
          readline.get_history_length())
    print('Startup history:', get_history_items())
    try:
        while True:
            line = input('Prompt ("stop" to quit): ')
            if line == 'stop':
                break
            if line:
                print('Adding {!r} to the history'.format(line))
    finally:
        print('Final history:', get_history_items())
        readline.write_history_file(HISTORY_FILENAME)


# Register our completer function
readline.set_completer(HistoryCompleter().complete)

# Use the tab key for completion
readline.parse_and_bind('tab: complete')

# Prompt the user for text
input_loop()