eliza.py

   1
   2 # coding: utf-8
   3 #import yaml
   4 import json
   5 import collections
   6 import random
   7
   8 Match = collections.namedtuple('Match', 'text, rule, bindings')
   9
  10 pronoun_swaps = {
  11     'i': 'you',
  12     'me': 'you',
  13     'my': 'your',
  14     'mine': 'yours',
  15     'am': 'are',
  16     'you': 'i',
  17     'your': 'my',
  18     'yours': 'mine'
  19 }
  20
  21 halt_words = 'quit halt exit stop'.split()
  22
  23 # def read_rules(rules_file):
  24 #     with open(rules_file) as f:
  25 #         rules = [{'pattern': r['pattern'].split(),
  26 #                  'responses': [t.split() for t in r['responses']]}
  27 #             for r in yaml.safe_load(f)]
  28 #    return rules
  29
  30 def read_rules(rules_file):
  31     with open(rules_file) as f:
  32         rules = [{'pattern': r['pattern'].split(),
  33                  'responses': [t.split() for t in r['responses']]}
  34             for r in json.load(f)]
  35     return rules
  36
  37 def is_var(word):
  38     return word[0] == '?'
  39
  40
  41 def splits(item):
  42     return [(item[:i], item[i:]) for i in range(len(item)+1)]
  43
  44 def match(text, rule):
  45     return all_matches([Match(text, rule, {})])
  46
  47 def all_matches(matches):
  48     successes = []
  49     while matches:
  50         # print(matches, successes)
  51         current = matches[0]
  52         new_matches = []
  53         if successful_match(current):
  54             successes += [current.bindings]
  55         elif current.rule:
  56             new_matches = match_item(current.text, current.rule, current.bindings)
  57         matches = matches[1:] + new_matches
  58     return successes
  59
  60 def successful_match(match):
  61     return match.text == [] and match.rule == []
  62
  63 def match_item(text, rule, bindings):
  64     r0 = rule[0]
  65     if is_var(r0):
  66         if r0 in bindings:
  67             # already seen this variable
  68             if text[:len(bindings[r0])] == bindings[r0]:
  69                 return [Match(text[(len(bindings[r0])):], rule[1:], bindings)]
  70             else:
  71                 return []
  72         else:
  73             # not seen this variable yet
  74             matches = []
  75             for pre, suf in splits(text):
  76                 new_bindings = bindings.copy()
  77                 new_bindings[r0] = pre
  78                 matches += [Match(suf, rule[1:], new_bindings)]
  79             return matches
  80     elif text and text[0] == r0:
  81         return [Match(text[1:], rule[1:], bindings)]
  82     else:
  83         return []
  84
  85 def candidate_rules(rules, comment):
  86     return [(rule, bindings)
  87             for rule in rules
  88             for bindings in match(comment, rule['pattern'])]
  89
  90
  91 def fill(response, bindings):
  92     filled_response = []
  93     for w in response:
  94         if is_var(w):
  95             if w in bindings:
  96                 filled_response += bindings[w]
  97             else:
  98                 filled_response += ['MISSING']
  99         else:
 100             filled_response += [w]
 101     return filled_response
 102
 103
 104 def pronoun_person_swap(bindings):
 105     def swapped(words):
 106         sw = []
 107         for w in words:
 108             if w in pronoun_swaps:
 109                 sw += [pronoun_swaps[w]]
 110             else:
 111                 sw += [w]
 112         return sw
 113
 114     return {var: swapped(bindings[var]) for var in bindings}
 115
 116 def respond(rule, bindings):
 117     return fill(random.choice(rule['responses']), bindings)
 118
 119
 120 def eliza_loop(rules):
 121     print("Hello. I'm Eliza. What seems to be the problem?")
 122     while True:
 123         c = input("> ")
 124         if c.strip() in halt_words: break
 125         comment = c.split()
 126         rule, bindings = candidate_rules(rules, comment)[0]
 127         swapped_bindings = pronoun_person_swap(bindings)
 128         print(' '.join(respond(rule, swapped_bindings)))
 129
 130
 131 all_rules = read_rules('rules.json')
 132 eliza_loop(all_rules)
 133
 134
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 138