diff options
| -rw-r--r-- | bs4/element.py | 130 |
1 files changed, 62 insertions, 68 deletions
diff --git a/bs4/element.py b/bs4/element.py index f4d5c40..7d84083 100644 --- a/bs4/element.py +++ b/bs4/element.py @@ -617,55 +617,42 @@ class PageElement(object): # already found direct descendants in last step. skip this # step. continue + + # Each operation corresponds to a candidate generator (a + # rule for finding tags that might match) and a checker function (a + # rule for determining whether a tag does match. + production_rule = None + checker = None + m = self.attribselect_re.match(token) if m is not None: # Attribute selector - tag, attribute, operator, value = m.groups() - if not tag: - tag = True + tag_name, attribute, operator, value = m.groups() + if not tag_name: + tag_name = True + production_rule = lambda tag: tag.find_all(tag_name) checker = self._attribute_checker(operator, attribute, value) - found = [] - for context in current_context: - found.extend( - [el for el in - context.find_all(tag, recursive=recursive) - if checker(el)]) - current_context = found - continue - if '#' in token: + elif '#' in token: # ID selector - tag, id = token.split('#', 1) - if tag == "": - tag = True - if len(current_context) == 0: - # No match. - return [] - el = current_context[0].find(tag, {'id': id}) - if el is None: - return [] # No match - current_context = [el] - continue + tag_name, id = token.split('#', 1) + if tag_name == "": + tag_name = True + production_rule = lambda tag: tag.find(tag_name, id=id) + checker = None - if '.' in token: + elif '.' in token: # Class selector tag_name, klass = token.split('.', 1) - if not tag_name: + if tag_name == '': tag_name = True classes = set(klass.split('.')) - found = [] - def classes_match(tag): - if tag_name is not True and tag.name != tag_name: - return False - if not tag.has_attr('class'): - return False - return classes.issubset(tag['class']) - for context in current_context: - found.extend(context.find_all(classes_match, recursive=recursive)) - current_context = found - continue + production_rule = lambda tag: tag.find_all(tag_name) + def classes_match(candidate): + return classes.issubset(tag.getattr('class', [])) + checker = classes_match - if ':' in token: + elif ':' in token: # Pseudoselector tag_name, pseudo = token.split(':', 1) if not tag_name: @@ -684,44 +671,51 @@ class PageElement(object): if pseudo_value < 1: raise ValueError( 'nth-of-type pseudoselector value must be at least 1.') - pseudo_value = pseudo_value - 1 - for context in current_context: - all_nodes = context.find_all(tag_name, recursive=recursive) - if pseudo_value < len(all_nodes): - found.extend([all_nodes[pseudo_value]]) - current_context = found - continue + count = 0 + def checker(tag): + if tag.name == tag_name: + count += 1 + if pseudo_value == count: + return True + return False + production_rule = lambda tag: tag.find_all(tag_name, limit=pseudo_value) + checker = checker else: raise NotImplementedError( - 'Only the nth-of-type pseudoselector is supported for now.') + 'The following pseudoselectors are implemented: nth-of-type.') - if token == '*': + elif token == '*': # Star selector - found = [] - for context in current_context: - found.extend(context.find_all(True, recursive=recursive)) - current_context = found - continue + production_rule = lambda tag: tag.find_all() + checker = lambda x: True - if token == '>': + elif token == '>': # Child selector - tag = tokens[index + 1] - if not tag: - tag = True + # TODO If this is the last token, there's a problem. + next_selector = tokens[index + 1] + production_rule = lambda tag: tag.select(next_selector) + checker = lambda candidate: True + + elif self.tag_name_re.match(token): + tag_name = token + production_rule = lambda tag: tag.find_all(tag_name) + checker = lambda candidate: True + else: + raise ValueError( + 'Unsupported or invalid CSS selector: "%s"' % token) + + # We now have a production rule and a checker. Apply the + # production rule to every member of the new context to + # find candidates. Check each candidate against the + # checker. The new context is the set of candidates that + # pass the checker. + new_context = [] + for tag in current_context: + for candidate in production_rule(tag): + if checker(candidate): + new_context.append(candidate) + current_context = new_context - found = [] - for context in current_context: - found.extend(context.select(tag, recursive=False)) - current_context = found - continue - - # Here we should just have a regular tag - if not self.tag_name_re.match(token): - return [] - found = [] - for context in current_context: - found.extend(context.find_all(token, recursive=recursive)) - current_context = found return current_context # Old non-property versions of the generators, for backwards |