Markov: add punctuation between chains

when starting a second (or Nth) chain because the results so far
are too short, add punctuation to the end of the chain, just to
make things feel a bit more natural

modules/Markov.py

@@ -406,6 +406,14 @@ class Markov(Module):
                     if gen_words[-1] == self.stop:
                         gen_words = gen_words[:-1]
 
+                    # monkey with the end word to make it more like an actual sentence end
+                    sentence_end = gen_words[-1]
+                    eos_punctuation = ['!', '?', ',', '.']
+                    if sentence_end[-1] not in eos_punctuation:
+                        random.shuffle(eos_punctuation)
+                        gen_words[-1] = sentence_end + eos_punctuation.pop()
+                        self.log.debug("monkeyed with end of sentence, it's now: {0:s}".format(gen_words[:-1]))
+
                     # new word 1
                     key_hits = self._retrieve_chains_for_key(self.start1, self.start2, context_id)
                     gen_words.append(self._get_suitable_word_from_choices(key_hits, gen_words, min_size))