def _parse_op(self, op_name):
self._get_token() # '('
op = self._transformations.get(op_name, None)
if op is None:
raise errors.IndexDefinitionParseError("Unknown operation: %s" %
op_name)
args = []
while True:
args.append(self._parse_term())
sep = self._get_token()
if sep == ')':
break
if sep != ',':
raise errors.IndexDefinitionParseError(
"Unexpected token '%s' in parentheses." % (sep, ))
parsed = []
for i, arg in enumerate(args):
arg_type = op.args[i % len(op.args)]
if arg_type == 'expression':
inner = self._to_getter(arg)
else:
try:
inner = arg_type(arg)
except ValueError as e:
raise errors.IndexDefinitionParseError(
"Invalid value %r for argument type %r "
"(%r)." % (arg, arg_type, e))
parsed.append(inner)
return op(*parsed)
def _parse_term(self):
term = self._get_token()
if term is None:
raise errors.IndexDefinitionParseError(
"Unexpected end of index definition.")
if term in (',', ')', '('):
raise errors.IndexDefinitionParseError(
"Unexpected token '%s' at start of expression." % (term, ))
next_token = self._peek_token()
if next_token == '(':
return self._parse_op(term)
return term
def parse(self, expression):
self._set_expression(expression)
term = self._to_getter(self._parse_term())
if self._peek_token():
raise errors.IndexDefinitionParseError(
"Unexpected token '%s' after end of expression." %
(self._peek_token(), ))
return term
def check_fieldname(fieldname):
if fieldname.endswith('.'):
raise errors.IndexDefinitionParseError(
"Fieldname cannot end in '.':%s^" % (fieldname, ))