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Postings from October 2014
Hi,
On 10/18/2014 07:06 PM, Father Chrysostomos wrote:
> Steffen Mueller wrote:
>> On 10/18/2014 06:56 AM, Father Chrysostomos wrote:
>>> BTW, a simplistic benchmark like this shows a 10% speed increase with
>>> the list+pushmark optimisation disabled:
>>>
>>> $ time ./miniperl -e 'for(1..20000000){() = (0,my($b,$c))}'
>>
>> Do you have any idea if this might be also relevant to code that's not
>> completely contrived?
>
> No, not in blead. (Nor can I think of a non-contrived example where
> your list+pushmark-in-list-context optimisation helps. If you could
> provide one, that would help put things in perspective.)
Examples: Slices, certain map expressions (if they return more than one
element).
See also:
http://blog.booking.com/more-optimizations-in-perl-5.20-to-be.html (a
bit drawn out in explanations for you, sorry).
> But if I move the list+pushmark optimisation to
> the context-application phase as proposed in
> <20141017162522.32689.qmail@lists-nntp.develooper.com>, then it would
> affect code like map { $this_lexical, $that_lexical, ... }, which is
> admitted still contrived, though I can imagine it being more likely to
> happen in the wild than (0,my($a,$b)).
I don't think that's so contrived at all, by the way. Extending lists
with map isn't so uncommon.
Best regards,
Steffen
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