[#boost-urls-grammar-lut_chars]
= xref:boost.adoc[boost]::xref:boost/urls.adoc[urls]::xref:boost/urls/grammar.adoc[grammar]::lut&lowbar;chars
:relfileprefix: ../../../
:mrdocs:


A set of characters

== Synopsis


Declared in `&lt;https://www.github.com/boostorg/url/blob/develop/include/boost/url/grammar/lut_chars.hpp#L64[boost&sol;url&sol;grammar&sol;lut&lowbar;chars&period;hpp]&gt;`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
class lut&lowbar;chars;
----

== Member Functions

[cols=2]
|===
| Name | Description 

| xref:boost/urls/grammar/lut_chars/2constructor.adoc[`lut&lowbar;chars`]         [.small]#[constructor]#
| Constructor

Constructor&period;


| xref:boost/urls/grammar/lut_chars/operator_call.adoc[`operator()`] 
| Return true if ch is in the character set&period;


| xref:boost/urls/grammar/lut_chars/operator_bitnot.adoc[`operator&#126;`] 
| Return a new character set which is the complement of another character set&period;

|===
== Friends

[cols=2]
|===
| Name | Description 

| xref:boost/urls/grammar/lut_chars/08friend-02.adoc[`operator&plus;`] 
| Return the union of two character sets&period;

| xref:boost/urls/grammar/lut_chars/08friend-07.adoc[`operator&hyphen;`] 
| Return a new character set by subtracting

|===



== Description


The characters defined by instances of    this set are provided upon construction&period;    The `constexpr` implementation allows    these to become compile&hyphen;time constants&period;


=== Example

Character sets are used with rules and the    functions xref:boost/urls/grammar/find_if.adoc[find&lowbar;if] and xref:boost/urls/grammar/find_if_not.adoc[find&lowbar;if&lowbar;not]&period;

[,cpp]
----
constexpr lut_chars vowel_chars = "AEIOU" "aeiou";

system::result< core::string_view > rv = parse( "Aiea", token_rule( vowel_chars ) );
----


== See Also


xref:boost/urls/grammar/find_if.adoc[find&lowbar;if],        xref:boost/urls/grammar/find_if_not.adoc[find&lowbar;if&lowbar;not],        xref:boost/urls/grammar/parse-02.adoc[parse],        xref:boost/urls/grammar/token_rule.adoc[token&lowbar;rule]&period;






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