def parse(self) -> InstanceRoute:
        """Parse instance identifier."""
        res = InstanceRoute()
        while True:
            self.char("/")
            res.append(MemberName(*self.prefixed_name()))
            try:
                next = self.peek()
            except EndOfInput:
                return res
            if next == "[":
                self.offset += 1
                self.skip_ws()
                next = self.peek()
                if next in "0123456789":
                    ind = self.unsigned_integer() - 1
                    if ind < 0:
                        raise UnexpectedInput(self, "positive index")
                    self.skip_ws()
                    self.char("]")
                    res.append(EntryIndex(ind))
                elif next == '.':
                    self.offset += 1
                    res.append(EntryValue(self._get_value()))
                else:
                    res.append(self._key_predicates())
                if self.at_end():
                    return res
Parse instance identifier.