Header file universal_reference.hpp

#define SIPLASPLAS_UTILITY_UNIVERSALREFERENCE_HPP 

#include <type_traits>

#include <bitset>

namespace cpp
{
    template <typename T, bool IsLvalueReference, bool IsConst>
    class UniversalReference;
    
    template <typename T>
    class UniversalReference<
    T,
    true,
    false
    >;
    
    template <typename T>
    class UniversalReference<
    T,
    false,
    false
    >;
    
    template <typename T>
    UniversalReference<
    std::decay_t<T>,
    std::is_lvalue_reference<T>::value,
    std::is_const<std::remove_reference_t<T>>::value
    > universalReference(T&& value);
}

Class template cpp::UniversalReference<T, IsLvalueReference, IsConst>

template <typename T, bool IsLvalueReference, bool IsConst>
class UniversalReference
{
public:
    using ValueType = T;
    
    UniversalReference(const ValueType& lvalueRef);
    
    const ValueType& get() const;
};

This template and its specialization provides a common interface to store references to lvalue and rvalues. UniversalReference has different spacializations for each value category supported (reference to lvalue, const reference to lvalue, rvalue). Instances of this types should be created through cpp::universalReference() function, which instances the appropiate template given the input value category.

If the input value is an lvalue (i.e. the function parameter is a reference to an lvalue), UniversalReference specialization wrapping the reference is chosen. If the input value is an rvalue (the function parameter is a reference to an rvalue), the value is moved into the UniversalReference object and owned by it.

This main template is the specialization for const lvalues

Function cpp::UniversalReference<T, IsLvalueReference, IsConst>::get

const ValueType& get() const;

Returns a read only reference to the referenced object

Class template `cpp::UniversalReference<

T, true, false >`

template <typename T>
class UniversalReference<
T,
true,
false
>
{
public:
    using ValueType = T;
    
    UniversalReference(ValueType& lvalueRef);
    
    ValueType& get() const;
};

See cpp::UniversalReference main template documentation for details

Function `cpp::UniversalReference<

T, true, false >::get`

ValueType& get() const;

Returns a reference to the referenced object

Class template `cpp::UniversalReference<

T, false, false >`

template <typename T>
class UniversalReference<
T,
false,
false
>
{
public:
    using ValueType = T;
    
    UniversalReference(ValueType&& rvalueRef);
    
    ValueType& get();
    
    const ValueType& get() const;
};

See cpp::UniversalReference main template documentation for details

Function `cpp::UniversalReference<

T, false, false >::get`

ValueType& get();

Returns a reference to the referenced object

Function `cpp::UniversalReference<

T, false, false >::get`

const ValueType& get() const;

Returns a reference to the referenced object

Function template cpp::universalReference<T>

template <typename T>
UniversalReference<
std::decay_t<T>,
std::is_lvalue_reference<T>::value,
std::is_const<std::remove_reference_t<T>>::value
> universalReference(T&& value);

This function checks the value category of the given value and instances the apropiate cpp::UniversalReference specialization. Note the returned type depends on the value category. For an alternative with common a type, see cpp::typeerasure::AnyArg

Returns: A UniversalReference specialization instance as follows: