beman::optional::operator<

Synopses

Declared in <beman/optional/optional.hpp>

Orders two optionals with less-than.

template<
    typename T,
    typename U>
constexpr
bool
operator<(
    optional<T> const& lhs,
    optional<U> const& rhs)
requires detail::optional_lt_rel<T, U>;

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Orders an optional before a value with less-than.

template<
    typename T,
    typename U>
constexpr
bool
operator<(
    optional<T> const& lhs,
    U const& rhs)
requires (!detail::is_optional<U>) && detail::optional_lt_rel<T, U>;

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Orders a value before an optional with less-than.

template<
    typename T,
    typename U>
constexpr
bool
operator<(
    T const& lhs,
    optional<U> const& rhs)
requires (!detail::is_optional<T>) && detail::optional_lt_rel<T, U>;

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Return Value

true if lhs orders before rhs; a disengaged optional orders before any engaged one.
true if lhs is disengaged, or its contained value orders before rhs.
true if rhs is engaged and lhs orders before its contained value.

Parameters

Name	Description
lhs	The left-hand optional.
rhs	The right-hand optional.