def parseQuery(self, query):
# Lexical analysis.
tokens = _tokenizer_regex.findall(query)
self._tokens = tokens
# classify tokens
self._tokentypes = [_keywords.get(token.upper(), _ATOM)
for token in tokens]
# add _EOF
self._tokens.append(_EOF)
self._tokentypes.append(_EOF)
self._index = 0
# Syntactical analysis.
self._ignored = [] # Ignored words in the query, for parseQueryEx
tree = self._parseOrExpr()
self._require(_EOF)
if tree is None:
raise parsetree.ParseError(
"Query contains only common words: %s" % repr(query))
return tree
def _parseTerm(self):
if self._check(_LPAREN):
tree = self._parseOrExpr()
self._require(_RPAREN)
else:
nodes = []
nodes = [self._parseAtom()]
while self._peek(_ATOM):
nodes.append(self._parseAtom())
nodes = filter(None, nodes)
if not nodes:
return None # Only stopwords
structure = [(isinstance(nodes[i], parsetree.NotNode), i, nodes[i])
for i in range(len(nodes))]
structure.sort()
nodes = [node for (_, index, node) in structure]
if isinstance(nodes[0], parsetree.NotNode):
raise parsetree.ParseError(
"a term must have at least one positive word")
if len(nodes) == 1:
return nodes[0]
tree = parsetree.AndNode(nodes)
return tree
def _require(self, tokentype):
if not self._check(tokentype):
t = self._tokens[self._index]
msg = "Token %r required, %r found" % (tokentype, t)
raise parsetree.ParseError(msg)