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More concepts to drive comparisons.

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ADAM David Alan Martin
2025-08-28 00:03:25 -04:00
parent 970c65c7ea
commit 5dd58a1a06
1 changed files with 11 additions and 23 deletions
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34
comparisons.h
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@ -110,20 +110,20 @@ namespace Alepha::Hydrogen
return spaceship_lens( t );
}
template< typename T, typename= void >
struct supports_value_lens : std::false_type {};
template< typename T >
struct supports_value_lens< T, std::void_t< decltype( value_lens( std::declval< const T & >() ) ) > > : std::true_type {};
template< typename T >
constexpr bool supports_value_lens_v= supports_value_lens< T >::value;
concept ValueLensed=
Comparable< T >
and
requires( const T &val )
{
{ value_lens( val ) } -> Concepts::Comparable;
};
template< typename T >
constexpr decltype( auto )
make_value_lens( T &t )
{
if constexpr( supports_value_lens_v< T > ) return value_lens( t );
if constexpr( ValueLensed< T > ) return value_lens( t );
//else if constexpr( supports_default_lens_v< T > ) return default_lens( t );
else static_assert( Meta::dep_value< false, T > );
}
@ -140,19 +140,13 @@ namespace Alepha::Hydrogen
};
constexpr decltype( auto )
equality_lens( MemberEqualityLensed auto &t )
equality_lens( const MemberEqualityLensed auto &t )
{
return t.equality_lens();
}
template
<
Comparable T,
typename= std::enable_if_t< supports_value_lens_v< T > >,
overload< __LINE__ > = nullptr
>
constexpr decltype( auto )
equality_lens( T &t )
equality_lens( const ValueLensed auto &t )
{
return value_lens( t );
}
@ -198,14 +192,8 @@ namespace Alepha::Hydrogen
return t.strict_weak_order_lens();
}
template
<
Comparable T,
typename= std::enable_if_t< supports_value_lens_v< T > >,
overload< __LINE__ > = nullptr
>
constexpr decltype( auto )
strict_weak_order_lens( T &t )
strict_weak_order_lens( const ValueLensed auto &t )
{
return value_lens( t );
}