:relfileprefix: ../../../../
[#boost-urls-grammar-implementation_defined-optional_rule_t]

== xref:boost.adoc[pass:[boost]]::xref:boost/urls.adoc[pass:[urls]]::xref:boost/urls/grammar.adoc[pass:[grammar]]::xref:boost/urls/grammar/implementation_defined.adoc[pass:[implementation_defined]]::optional_rule_t



=== Synopsis

Declared in header `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/grammar/optional_rule.hpp#L66[boost/url/grammar/optional_rule.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
template<class Rule>
struct optional_rule_t;
----

===  Types
[cols=2,separator=¦]
|===
¦Name ¦Description
¦xref:boost/urls/grammar/implementation_defined/optional_rule_t/value_type.adoc[`value_type`]  ¦

|===
===  Member Functions
[cols=2,separator=¦]
|===
¦Name ¦Description
¦xref:boost/urls/grammar/implementation_defined/optional_rule_t/2constructor.adoc[`optional_rule_t`] [.small]#[constructor]# ¦

¦xref:boost/urls/grammar/implementation_defined/optional_rule_t/parse.adoc[`parse`]  ¦

|===