def _Eval(self, node):
if node.getType() is ExpressionParser.FN:
func = self._function_table[query_parser.GetQueryNodeText(node)]
return func(*node.children)
if node.getType() is ExpressionParser.PLUS:
return self._EvalBinaryOp(lambda a, b: a + b, 'addition', node)
if node.getType() is ExpressionParser.MINUS:
return self._EvalBinaryOp(lambda a, b: a - b, 'subtraction', node)
if node.getType() is ExpressionParser.DIV:
return self._EvalBinaryOp(lambda a, b: a / b, 'division', node)
if node.getType() is ExpressionParser.TIMES:
return self._EvalBinaryOp(lambda a, b: a * b, 'multiplication',
node)
if node.getType() is ExpressionParser.NEG:
return self._EvalUnaryOp(lambda a: -a, 'negation', node)
if node.getType() in (ExpressionParser.INT, ExpressionParser.FLOAT):
return float(query_parser.GetQueryNodeText(node))
if node.getType() is ExpressionParser.PHRASE:
return query_parser.GetQueryNodeText(node).strip('"')
if node.getType() is ExpressionParser.NAME:
name = query_parser.GetQueryNodeText(node)
if name == '_score':
return self._doc.score
field = search_util.GetFieldInDocument(self._doc_pb, name)
if field:
return search_util.GetFieldValue(field)
raise _ExpressionError('No field %s in document' % name)
raise _ExpressionError('Unable to handle node %s' % node)
def _Snippet(self, query, field, *args):
"""Create a snippet given a query and the field to query on.
Args:
query: A query string containing only a bare term (no operators).
field: The field name to query on.
*args: Unused optional arguments. These are not used on dev_appserver.
Returns:
A snippet for the field with the query term bolded.
"""
field = query_parser.GetQueryNodeText(field)
terms = self._tokenizer.TokenizeText(
query_parser.GetQueryNodeText(query).strip('"'))
for term in terms:
search_token = tokens.Token(chars=u'%s:%s' % (field, term.chars))
postings = self._inverted_index.GetPostingsForToken(search_token)
for posting in postings:
if posting.doc_id != self._doc_pb.id(
) or not posting.positions:
continue
field_val = search_util.GetFieldValue(
search_util.GetFieldInDocument(self._doc_pb, field))
if not field_val:
continue
doc_words = [
token.chars for token in
self._case_preserving_tokenizer.TokenizeText(field_val)
]
position = posting.positions[0]
return self._GenerateSnippet(
doc_words, position,
search_util.DEFAULT_MAX_SNIPPET_LENGTH)
else:
field_val = search_util.GetFieldValue(
search_util.GetFieldInDocument(self._doc_pb, field))
if not field_val:
return None
return '%s...' % field_val[:search_util.
DEFAULT_MAX_SNIPPET_LENGTH]
def _Eval(self, node):
"""Evaluate an expression node on the document.
Args:
node: The expression AST node representing an expression subtree.
Returns:
The Python value that maps to the value of node. Types are inferred from
the expression, so expressions with numeric results will return as python
int/long/floats, textual results will be strings, and dates will be
datetimes.
Raises:
_ExpressionError: The expression cannot be evaluated on this document
because either the expression is malformed or the document does not
contain the required fields. Callers of _Eval should catch
_ExpressionErrors and optionally log them; these are not fatal in any way,
and are used to indicate that this expression should not be set on this
document.
"""
if node.getType() in self._function_table:
func = self._function_table[node.getType()]
return func(*node.children)
if node.getType() == ExpressionParser.PLUS:
return self._EvalBinaryOp(lambda a, b: a + b, 'addition', node)
if node.getType() == ExpressionParser.MINUS:
return self._EvalBinaryOp(lambda a, b: a - b, 'subtraction', node)
if node.getType() == ExpressionParser.DIV:
return self._EvalBinaryOp(lambda a, b: a / b, 'division', node)
if node.getType() == ExpressionParser.TIMES:
return self._EvalBinaryOp(lambda a, b: a * b, 'multiplication',
node)
if node.getType() == ExpressionParser.NEG:
return self._EvalUnaryOp(lambda a: -a, 'negation', node)
if node.getType() in (ExpressionParser.INT, ExpressionParser.FLOAT):
return float(query_parser.GetQueryNodeText(node))
if node.getType() == ExpressionParser.PHRASE:
return query_parser.GetQueryNodeText(node).strip('"')
if node.getType() == ExpressionParser.NAME:
name = query_parser.GetQueryNodeText(node)
if name == '_score':
return self._doc.score
field = search_util.GetFieldInDocument(self._doc_pb, name)
if field:
return search_util.GetFieldValue(field)
raise _ExpressionError('No field %s in document' % name)
raise _ExpressionError('Unable to handle node %s' % node)
def _Snippet(self, query, field, *args):
field = query_parser.GetQueryNodeText(field)
terms = self._tokenizer.TokenizeText(
query_parser.GetQueryNodeText(query).strip('"'))
for term in terms:
search_token = tokens.Token(chars=u'%s:%s' % (field, term.chars))
postings = self._inverted_index.GetPostingsForToken(search_token)
for posting in postings:
if posting.doc_id != self._doc_pb.id(
) or not posting.positions:
continue
field_val = search_util.GetFieldValue(
search_util.GetFieldInDocument(self._doc_pb, field))
doc_words = [
token.chars for token in
self._case_preserving_tokenizer.TokenizeText(field_val)
]
position = posting.positions[0]
return self._GenerateSnippet(
doc_words, position,
search_util.DEFAULT_MAX_SNIPPET_LENGTH)
