forked from Alepha/Alepha
35 lines
1.1 KiB
C++
35 lines
1.1 KiB
C++
static_assert( __cplusplus > 2020'99 );
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#pragma once
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#include <Alepha/Alepha.h>
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namespace Alepha::Hydrogen::Algorithm ::detail:: identity_m
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{
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inline namespace exports
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{
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/*!
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* Specializable identity function.
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*
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* Sometimes you need an unambiguous overload for `std::identity`. Because the
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* standard's version is a function object with an unbounded member template
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* `operator ()`, this means that deduction contexts cannod deduce which
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* type is the range and domain for the identity object passed. Normally
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* this doesn't matter, but some `Alepha` constructs need to inspect functions.
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* to that end, one can use `Alepha::Algorithm::identity< T >` for this purpose
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*
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* @note This functions effectively the same as the original SGI STL's `identity`
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* extension, but with C++11's rvalue semantics. Although we also use a template
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* variable to avoid the need to instantiate.
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*/
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template< typename T >
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constexpr auto identity= []( T val ) { return val; };
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}
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}
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namespace Alepha::Hydrogen::Algorithm::inline exports::inline identity_m
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{
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using namespace detail::identity_m::exports;
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}
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