arg_router::utility::compile_time_optional< T > Class Template Reference

#include <arg_router/utility/compile_time_optional.hpp>

Public Types
using	value_type = T

Public Member Functions
constexpr	compile_time_optional (value_type val) noexcept
constexpr	operator bool () const
constexpr const value_type *	operator-> () const noexcept
constexpr const value_type &	operator* () const noexcept
value_type *	operator-> () noexcept
value_type &	operator* () noexcept

Static Public Attributes
constexpr static bool	empty = false

Detailed Description

template<typename T>
class arg_router::utility::compile_time_optional< T >

Compile-time equivalent of std::optional.

std::optional can be used in compile-time expressions, but not when used as a argument, this class can do that but comes with severe runtime limitations due to it.

An empty optional cannot be created and then populated later, nor cleared, as that state is a part of its template parameters (a void type is an empty compile_time_optional).

Like std::optional references cannot be stored internally, but it can use a std::reference_wrapper. Unlike std::optional this type has a specialisation that makes the std::reference_wrapper access transparent (i.e. you don't need to dereference twice).

Note

The std::reference_wrapper specialisation is not constexpr

Template Parameters

T	Value type

Definition at line 29 of file compile_time_optional.hpp.

Member Typedef Documentation

value_type

template<typename T >

using arg_router::utility::compile_time_optional< T >::value_type = T

Value type.

Definition at line 33 of file compile_time_optional.hpp.

Constructor & Destructor Documentation

compile_time_optional()

template<typename T >

constexpr arg_router::utility::compile_time_optional< T >::compile_time_optional ( value_type  val )

inlineexplicitconstexprnoexcept

Constructor.

Parameters

val	Value to copy into the optional

Definition at line 42 of file compile_time_optional.hpp.

Member Function Documentation

operator bool()

template<typename T >

constexpr arg_router::utility::compile_time_optional< T >::operator bool ( ) const

inlineexplicitconstexpr

Implicit bool conversion operator.

Returns

True if not empty

Definition at line 48 of file compile_time_optional.hpp.

operator*() [1/2]

template<typename T >

constexpr const value_type& arg_router::utility::compile_time_optional< T >::operator* ( ) const

inlineconstexprnoexcept

Dereference operator.

Note

Not available if empty

Returns

Reference

Definition at line 62 of file compile_time_optional.hpp.

operator*() [2/2]

template<typename T >

value_type& arg_router::utility::compile_time_optional< T >::operator* ( )

inlinenoexcept

Non-const overload.

Note

Not available if empty

Returns

Reference

Definition at line 76 of file compile_time_optional.hpp.

operator->() [1/2]

template<typename T >

constexpr const value_type* arg_router::utility::compile_time_optional< T >::operator-> ( ) const

inlineconstexprnoexcept

Dereference to member operator.

Note

Not available if empty

Returns

Pointer

Definition at line 55 of file compile_time_optional.hpp.

operator->() [2/2]

template<typename T >

value_type* arg_router::utility::compile_time_optional< T >::operator-> ( )

inlinenoexcept

Non-const overload.

Note

Not available if empty

Returns

Pointer

Definition at line 69 of file compile_time_optional.hpp.

Member Data Documentation

empty

template<typename T >

constexpr static bool arg_router::utility::compile_time_optional< T >::empty = false

staticconstexpr

True if empty.

Definition at line 36 of file compile_time_optional.hpp.

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The documentation for this class was generated from the following file:

• arg_router/utility/compile_time_optional.hpp