+ +    def item_w(self, w_item): +        space=self.space +        if self.typecode == 'c': +            return self.space.str_w(w_item) +        elif self.typecode == 'u': +            return self.space.unicode_w(w_item) + +        elif self.typecode == 'b': +            item=self.space.int_w(w_item) +            if item<-128: +                msg='signed char is less than minimum' +                raise OperationError(space.w_OverflowError, space.wrap(msg)) +            elif item>127: +                msg='signed char is greater than maximum' +                raise OperationError(space.w_OverflowError, space.wrap(msg)) +            return rffi.cast(rffi.SIGNEDCHAR, item) +        elif self.typecode == 'B': +            item=self.space.int_w(w_item) +            if item<0: +                msg='unsigned byte integer is less than minimum' +                raise OperationError(space.w_OverflowError, space.wrap(msg)) +            elif item>255: +                msg='unsigned byte integer is greater than maximum' +                raise OperationError(space.w_OverflowError, space.wrap(msg)) +            return rffi.cast(rffi.UCHAR, item) + +        elif self.typecode == 'h': +            item=self.space.int_w(w_item) +            if item<-32768: +                msg='signed short integer is less than minimum' +                raise OperationError(space.w_OverflowError, space.wrap(msg)) +            elif item>32767: +                msg='signed short integer is greater than maximum' +                raise OperationError(space.w_OverflowError, space.wrap(msg)) +            return rffi.cast(rffi.SHORT, item) +        elif self.typecode == 'H': +            item=self.space.int_w(w_item) +            if item<0: +                msg='unsigned short integer is less than minimum' +                raise OperationError(space.w_OverflowError, space.wrap(msg)) +            elif item>65535: +                msg='unsigned short integer is greater than maximum' +                raise OperationError(space.w_OverflowError, space.wrap(msg)) +            return rffi.cast(rffi.USHORT, item) + +        elif self.typecode in ('i', 'l'): +            item=self.space.int_w(w_item) +            if item<-2147483648: +                msg='signed integer is less than minimum' +                raise OperationError(space.w_OverflowError, space.wrap(msg)) +            elif item>2147483647: +                msg='signed integer is greater than maximum' +                raise OperationError(space.w_OverflowError, space.wrap(msg)) +            return rffi.cast(lltype.Signed, item) +        elif self.typecode in ('I', 'L'): +            item=self.space.int_w(w_item) +            if item<0: +                msg='unsigned integer is less than minimum' +                raise OperationError(space.w_OverflowError, space.wrap(msg)) +            elif item>4294967295: +                msg='unsigned integer is greater than maximum' +                raise OperationError(space.w_OverflowError, space.wrap(msg)) +            return rffi.cast(lltype.Unsigned, item) + +        elif self.typecode == 'f': +            item=self.space.float_w(w_item) +            return rffi.cast(lltype.SingleFloat, item) +        elif self.typecode == 'd': +            return self.space.float_w(w_item) +

Hey. This looks a bit ugly, you can definitely do it with some constant dict or something (we have special support for iterating over constants and unrolling the iteration, look for unrolling_iterable). Also, annotator can fold a bunch of ifs into a switch, but not if "in" operator is used (or is fine though).