A really basic completer for prompt_toolkit

completer.py

from __future__ import print_function, unicode_literals

from prompt_toolkit.completion import Completer, Completion


class PwnCompleter(Completer):

    cmds = {'quit': None,
            'exit': None,
            'use': ['/foo/bar', '/herp/derp', '/baz/qux'],
            'info': ['test', '123'],
            'show': None,
            'shell': None}

    meta_dict = {'exit': 'Quit the program',
                 'shell': 'Drop to a shell' }

    def __init__(self, modules):
        self.modules = modules
        self.categories = list(modules.keys())
        self.base_cmds = list(self.cmds.keys())

    def get_completions(self, document, complete_event):
        word_before_cursor = document.get_word_before_cursor(WORD=True).lower()
        all_text = document.text_before_cursor
        try:
            last_word = all_text.split()[-1]
            first_word = all_text.split()[0]
        except IndexError:
            first_word = None
            # if there is no text assign base completions
            completions = self.base_cmds

        if first_word:
            try:
                if self.cmds[first_word] is not None:
                    completions = self.cmds[first_word]
                else:
                    completions = []
            except KeyError:
                completions = self.base_cmds

        completions.sort()

        for item in completions:
            if word_before_cursor in item:
                display_meta = self.meta_dict.get(item, '')
                yield Completion(item,
                                 -len(word_before_cursor),
                                 display_meta=display_meta)