[pypy-dev] The correct way to incrementally build list in RPython

Yichao Yu yyc1992 at gmail.com
Fri Jun 27 15:17:26 CEST 2014


On Fri, Jun 27, 2014 at 6:37 PM, Armin Rigo <arigo at tunes.org> wrote:
> Hi Yichao,
>
> On 27 June 2014 12:17, Yichao Yu <yyc1992 at gmail.com> wrote:
>> I am still creating a tuple out of these 5 numbers/strings since I
>> don't want to duplicate the hash functions for all of them. Can the
>> compiler deal with this case efficiently?
>
> If by "deal with this case efficiently" you mean, will the compiler
> remove the tuple allocation and inline the 5-elements hash, then it
> might just be possible depending on a number of details, but I doubt
> it.  Better to be explicit.  I had in mind something like:
>
>     my_hash = num1 * 1000003
>     my_hash = (my_hash ^ num2) * 1000003
>     my_hash = (my_hash ^ compute_hash(string3))
>     my_hash = intmask(my_hash)   # at the end
>

Done

>
> A bientôt,
>
> Armin.


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