[#boost-urls-grammar-token_rule-01]
= xref:boost.adoc[boost]::xref:boost/urls.adoc[urls]::xref:boost/urls/grammar.adoc[grammar]::token_rule
:relfileprefix: ../../../
:mrdocs:

Match a non‐empty string of characters from a default‐constructible set

== Synopsis

Declared in `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/grammar/token_rule.hpp#Lundefined[boost/url/grammar/token_rule.hpp]>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<xref:boost/urls/grammar/CharSet.adoc[CharSet] CharSet>
constexpr
/* implementation-defined */
token_rule() noexcept
requires std::is_default_constructible<CharSet>::value;
----

== Description

This overload is only available when CharSet is default constructible.

If there is no more input, the error code xref:boost/urls/grammar/error.adoc[`error::need_more`] is returned.

== Value Type

[,cpp]
----
using value_type = core::string_view;
----
== Example

Rules are used with the function xref:boost/urls/grammar/parse-09.adoc[`parse`].

[,cpp]
----
system::result< core::string_view > rv = parse( "abcdef", token_rule<alpha_chars_t>() );
----
== BNF

[,cpp]
----
token     = 1*( ch )
----
== Return Value

The token rule

== Template Parameters

[cols="1,4"]
|===
|Name|Description

| *CharSet*
| The character set type to use
|===

== See Also

xref:boost/urls/grammar/alpha_chars.adoc[`alpha&lowbar;chars`], xref:boost/urls/grammar/parse-09.adoc[`parse`]&period;


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