[#beman-optional-operator_lt-07]
= xref:beman.adoc[beman]::xref:beman/optional.adoc[optional]::operator<
:relfileprefix: ../../
:mrdocs:

Less‐than operators

== Synopses

Declared in `<beman/optional/optional.hpp>`

Orders two optionals with less‐than.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    typename T,
    typename U>
constexpr
bool
xref:beman/optional/operator_lt-0d.adoc[operator<](
    xref:beman/optional/optional-03.adoc[optional<T>] const& lhs,
    xref:beman/optional/optional-03.adoc[optional<U>] const& rhs)
requires detail::optional_lt_rel<T, U>;
----

[.small]#xref:beman/optional/operator_lt-0d.adoc[_» more..._]#

Orders an optional before a value with less‐than.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    typename T,
    typename U>
constexpr
bool
xref:beman/optional/operator_lt-08.adoc[operator<](
    xref:beman/optional/optional-03.adoc[optional<T>] const& lhs,
    U const& rhs)
requires (!detail::is_optional<U>) && detail::optional_lt_rel<T, U>;
----

[.small]#xref:beman/optional/operator_lt-08.adoc[_» more..._]#

Orders a value before an optional with less‐than.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    typename T,
    typename U>
constexpr
bool
xref:beman/optional/operator_lt-04.adoc[operator<](
    T const& lhs,
    xref:beman/optional/optional-03.adoc[optional<U>] const& rhs)
requires (!detail::is_optional<T>) && detail::optional_lt_rel<T, U>;
----

[.small]#xref:beman/optional/operator_lt-04.adoc[_» more..._]#

== 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

[cols="1,4"]
|===
| Name| Description
| *lhs*
| The left‐hand optional.
| *rhs*
| The right‐hand optional.
|===


[.small]#Created with https://www.mrdocs.com[MrDocs]#