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From: Desmond Gold Bongcawel <desmondbongcawel922_at_[hidden]>
Date: Tue, 26 Oct 2021 10:08:44 +0800
get has been defined as a function template in std::ranges for
std::ranges::subrange to obtain the pair of iterator and sentinel for
structured binding support. (if necessary)

My suggestion is that "get" for std::ranges::subrange should be defined in
namespace std for the CPO purposes of std::ranges::get or may be defined as
a member function template.

std::ranges::get will be redefined its name as a *customization point

>From the following definition, get is defined as a variable template where
the non-type template parameter I denotes the index of the tuple-like
inline namespace /* unspecified */ {
  template <size_t I>
  inline constexpr /* unspecified */ get = /* unspecified */;

A call to std::ranges::get
1. is expression-equivalent to "return get<I>(std::forward<Tup>(tup))"
    - where any declarations of get with appropriate template arguments can
be found in ADL.
2. otherwise, is expression-equivalent to "return
std::forward<Tup>(tup).template get<I>()"
    - where get is a member function template with appropriate template
3. otherwise, if the type is equal to an array type, then it is
expression-equivalent to "return tup[i]"

The potential benefits of std::ranges::get are to be encouraged used for
functions that use std::get for tuple-like to support user-defined types
such as std::apply in which internally used std::get where it prevents from
passing a user-defined type that has no std::get overload.

Received on 2021-10-25 21:08:57