forked from boostorg/optional
Added func value_or_eval()
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@ -35,7 +35,6 @@
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#include <boost/type_traits/remove_reference.hpp>
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#include <boost/type_traits/decay.hpp>
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#include <boost/type_traits/is_base_of.hpp>
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#include <boost/type_traits/is_convertible.hpp>
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#include <boost/type_traits/is_lvalue_reference.hpp>
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#include <boost/type_traits/is_nothrow_move_assignable.hpp>
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#include <boost/type_traits/is_nothrow_move_constructible.hpp>
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@ -51,7 +50,6 @@
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#include <boost/utility/addressof.hpp>
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#include <boost/utility/compare_pointees.hpp>
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#include <boost/utility/enable_if.hpp>
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#include <boost/utility/in_place_factory.hpp>
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#include <boost/utility/swap.hpp>
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@ -115,6 +113,27 @@ template<class T> void swap ( optional<T>& x, optional<T>& y );
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namespace optional_detail {
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// converts type U to type T using only implicit conversions/constructors
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#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
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template <typename TT, typename UU>
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TT convert(UU && u)
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{
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return forward<UU>(u);
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}
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#else
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template <typename TT, typename UU>
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TT convert(const UU& u)
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{
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return u;
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}
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template <typename TT, typename UU>
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TT convert(UU& u)
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{
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return u;
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}
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#endif
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// This local class is used instead of that in "aligned_storage.hpp"
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// because I've found the 'official' class to ICE BCB5.5
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// when some types are used with optional<>
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@ -1010,7 +1029,7 @@ class optional : public optional_detail::optional_base<T>
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#ifndef BOOST_NO_CXX11_REF_QUALIFIERS
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reference_const_type operator *() const& { return this->get() ; }
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reference_type operator *() & { return this->get() ; }
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reference_type_of_temporary_wrapper operator *() && { return boost::move(this->get()) ; }
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value_type operator *() && { return boost::move(this->get()) ; }
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#else
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reference_const_type operator *() const { return this->get() ; }
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reference_type operator *() { return this->get() ; }
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@ -1033,7 +1052,7 @@ class optional : public optional_detail::optional_base<T>
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throw_exception(bad_optional_access("Attempted to access the value of an uninitialized optional object."));
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}
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reference_type_of_temporary_wrapper value() &&
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value_type value() &&
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{
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if (this->is_initialized())
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return boost::move(this->get()) ;
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@ -1058,33 +1077,51 @@ class optional : public optional_detail::optional_base<T>
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}
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#endif
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#ifndef BOOST_NO_CXX11_REF_QUALIFIERS
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template <class U>
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value_type value_or ( U&& v ) const&
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{
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BOOST_STATIC_ASSERT((is_convertible<U&&, value_type>::value));
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return this->is_initialized() ? get() : static_cast<value_type>(boost::forward<U>(v));
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return this->is_initialized() ? get() : optional_detail::convert<value_type>(boost::forward<U>(v));
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}
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template <class U>
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value_type value_or ( U&& v ) &&
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{
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BOOST_STATIC_ASSERT((is_convertible<U&&, value_type>::value));
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return this->is_initialized() ? boost::move(get()) : static_cast<value_type>(boost::forward<U>(v));
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return this->is_initialized() ? boost::move(get()) : optional_detail::convert<value_type>(boost::forward<U>(v));
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}
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#elif !defined BOOST_NO_CXX11_RVALUE_REFERENCES
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template <class U>
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value_type value_or ( U&& v ) const
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{
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BOOST_STATIC_ASSERT((is_convertible<U&&, value_type>::value));
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return this->is_initialized() ? get() : static_cast<value_type>(boost::forward<U>(v));
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return this->is_initialized() ? get() : optional_detail::convert<value_type>(boost::forward<U>(v));
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}
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#else
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template <class U>
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value_type value_or ( U const& v ) const
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{
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BOOST_STATIC_ASSERT((is_convertible<U const&, value_type>::value));
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return this->is_initialized() ? get() : static_cast<value_type>(v);
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return this->is_initialized() ? get() : optional_detail::convert<value_type>(v);
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}
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#endif
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#ifndef BOOST_NO_CXX11_REF_QUALIFIERS
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template <typename F>
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value_type value_or_eval ( F f ) const&
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{
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return this->is_initialized() ? get() : optional_detail::convert<value_type>(f());
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}
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template <typename F>
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value_type value_or_eval ( F f ) &&
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{
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return this->is_initialized() ? boost::move(get()) : optional_detail::convert<value_type>(f());
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}
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#else
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template <typename F>
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value_type value_or_eval ( F f ) const
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{
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return this->is_initialized() ? get() : optional_detail::convert<value_type>(f());
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}
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#endif
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