220 29599 <18998acd-2c2e-713b-29d2-4874400b35b7@gmail.com> article
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From: Nikos Athanasiou <n.g.athanasiou@gmail.com>
Newsgroups: gmane.comp.lang.c++.isocpp.proposals
Subject: Re: Re: Add a "tuple_slice" function in <tuple>
Date: Thu, 1 Dec 2016 00:19:03 +0200
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Please refer to the related material, the proposed function does not=20
operate only on std::tuple. It works on any type/entity that is a valid=20
argument to std::tuple_size and std::get (namely std::array and=20
std::pair) - the reason why it's bound to produce "tuple slices" is=20
described in section 3 "Design consideration". I'm by no means implying=20
this is superior to generalized slicing, but merely more simple and not=20
requiring a language extension (plus it feels like it plays well with=20
the existing tuple toolkit - it doesn't need to introduce extra machinery)


On 30/11/2016 11:53 =CE=BC=CE=BC, Matthew Woehlke wrote:
> On 2016-11-30 16:04, =CE=9D=CE=B9=CE=BA=CF=8C=CE=BB=CE=B1=CE=BF=CF=82 =CE=
=91=CE=B8=CE=B1=CE=BD=CE=B1=CF=83=CE=AF=CE=BF=CF=85 wrote:
>> Just floating the idea before composing the complete text. I recently *b=
logged
>> <https://ngathanasiou.wordpress.com/2016/11/28/want-a-std-slice/>*about =
a
>> hypothetical tuple slice functionality (and related design consideration=
s)
>> and it seems useful & simple enough (conceptually and implementation wis=
e)
>> to be added in isolation to the Standard library (it may just have been
>> overlooked in previous versions, I couldn't find related proposals).
> If we had generalized slicing, would the proposed library function offer
> anything superior to `std::make_tuple([I1:I2]product_type...)`?
>
> (Generalized slicing would work both on *any* product type, as well as
> on parameter packs, so in at least that sense, it is superior to a
> library function that operates only on std::tuple.)
>

--=20
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