:relfileprefix: ../../../../
[#boost-urls-grammar-see_below-is_rule-05]

== xref:boost.adoc[pass:[boost]]::xref:boost/urls.adoc[pass:[urls]]::xref:boost/urls/grammar.adoc[pass:[grammar]]::xref:boost/urls/grammar/see_below.adoc[pass:[see_below]]::is_rule



=== Synopsis

Declared in header `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/grammar/type_traits.hpp#L27[boost/url/grammar/type_traits.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
template<class T>
struct xref:boost/urls/grammar/see_below/is_rule-0c.adoc[pass:[is_rule]]<T, void_t<decltype(std::declval<system::result<typename T::value_type>&>() =
                std::declval<T const&>().parse(
                    std::declval<char const*&>(),
                    std::declval<char const*>()))>>
    : std::is_nothrow_copy_constructible<T>;
----