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| @@ -266,7 +266,6 @@ class PunktLanguageVars: |
| return self._word_tokenizer_re().findall(s) |
| |
| _period_context_fmt = r""" |
| - \S* # some word material |
| %(SentEndChars)s # a potential sentence ending |
| (?=(?P<after_tok> |
| %(NonWord)s # either other punctuation |
| @@ -1284,8 +1283,7 @@ class PunktSentenceTokenizer(PunktBaseClass, TokenizerI): |
| See format_debug_decision() to help make this output readable. |
| """ |
| |
| - for match in self._lang_vars.period_context_re().finditer(text): |
| - decision_text = match.group() + match.group("after_tok") |
| + for match, decision_text in self._match_potential_end_contexts(text): |
| tokens = self._tokenize_words(decision_text) |
| tokens = list(self._annotate_first_pass(tokens)) |
| while tokens and not tokens[0].tok.endswith(self._lang_vars.sent_end_chars): |
| @@ -1333,10 +1331,68 @@ class PunktSentenceTokenizer(PunktBaseClass, TokenizerI): |
| """ |
| return [text[s:e] for s, e in self.span_tokenize(text, realign_boundaries)] |
| |
| + def _match_potential_end_contexts(self, text): |
| + """ |
| + Given a text, find the matches of potential sentence breaks, |
| + alongside the contexts surrounding these sentence breaks. |
| + |
| + Since the fix for the ReDOS discovered in issue #2866, we no longer match |
| + the word before a potential end of sentence token. Instead, we use a separate |
| + regex for this. As a consequence, `finditer`'s desire to find non-overlapping |
| + matches no longer aids us in finding the single longest match. |
| + Where previously, we could use:: |
| + |
| + >>> pst = PunktSentenceTokenizer() |
| + >>> text = "Very bad acting!!! I promise." |
| + >>> list(pst._lang_vars.period_context_re().finditer(text)) # doctest: +SKIP |
| + [<re.Match object; span=(9, 18), match='acting!!!'>] |
| + |
| + Now we have to find the word before (i.e. 'acting') separately, and `finditer` |
| + returns:: |
| + |
| + >>> pst = PunktSentenceTokenizer() |
| + >>> text = "Very bad acting!!! I promise." |
| + >>> list(pst._lang_vars.period_context_re().finditer(text)) # doctest: +NORMALIZE_WHITESPACE |
| + [<re.Match object; span=(15, 16), match='!'>, |
| + <re.Match object; span=(16, 17), match='!'>, |
| + <re.Match object; span=(17, 18), match='!'>] |
| + |
| + So, we need to find the word before the match from right to left, and then manually remove |
| + the overlaps. That is what this method does:: |
| + |
| + >>> pst = PunktSentenceTokenizer() |
| + >>> text = "Very bad acting!!! I promise." |
| + >>> pst._match_potential_end_contexts(text) |
| + [(<re.Match object; span=(17, 18), match='!'>, 'acting!!! I')] |
| + |
| + :param text: String of one or more sentences |
| + :type text: str |
| + :return: List of match-context tuples. |
| + :rtype: List[Tuple[re.Match, str]] |
| + """ |
| + before_words = {} |
| + matches = [] |
| + for match in reversed(list(self._lang_vars.period_context_re().finditer(text))): |
| + # Ignore matches that have already been captured by matches to the right of this match |
| + if matches and match.end() > before_start: |
| + continue |
| + # Find the word before the current match |
| + split = text[: match.start()].rsplit(maxsplit=1) |
| + before_start = len(split[0]) if len(split) == 2 else 0 |
| + before_words[match] = split[-1] |
| + matches.append(match) |
| + |
| + return [ |
| + ( |
| + match, |
| + before_words[match] + match.group() + match.group("after_tok"), |
| + ) |
| + for match in matches[::-1] |
| + ] |
| + |
| def _slices_from_text(self, text): |
| last_break = 0 |
| - for match in self._lang_vars.period_context_re().finditer(text): |
| - context = match.group() + match.group("after_tok") |
| + for match, context in self._match_potential_end_contexts(text): |
| if self.text_contains_sentbreak(context): |
| yield slice(last_break, match.end()) |
| if match.group("next_tok"): |
|
|
