:relfileprefix: ../../../
[#boost-urls-grammar-lut_chars]

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


A set of characters


== Synopsis

Declared in header `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/grammar/lut_chars.hpp#L64[boost/url/grammar/lut_chars.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
class lut_chars;
----

==  Member Functions
[cols=2,separator=¦]
|===
¦Name ¦Description
¦xref:boost/urls/grammar/lut_chars/find_if.adoc[`find_if`]  ¦

¦xref:boost/urls/grammar/lut_chars/find_if_not.adoc[`find_if_not`]  ¦

¦xref:boost/urls/grammar/lut_chars/2constructor.adoc[`lut_chars`] [.small]#[constructor]# ¦

Constructor

¦xref:boost/urls/grammar/lut_chars/operator_call.adoc[`operator()`]  ¦

Return true if ch is in the character set.

¦xref:boost/urls/grammar/lut_chars/operator_bitnot.adoc[`operator~`]  ¦

Return a new character set which is the complement of another character set.

|===
==  Friends
[cols=2,separator=¦]
|===
¦Name ¦Description
¦xref:boost/urls/grammar/lut_chars/08friend-02.adoc[`operator+`]  ¦

Return the union of two character sets.

¦xref:boost/urls/grammar/lut_chars/08friend-07.adoc[`operator-`]  ¦

Return a new character set by subtracting

|===

== Description


The characters defined by instances of
this set are provided upon construction.
The `constexpr` implementation allows
these to become compile-time constants.

=== Example

Character sets are used with rules and the
functions
xref:boost/urls/grammar/lut_chars/find_if.adoc[find_if]
and
xref:boost/urls/grammar/lut_chars/find_if_not.adoc[find_if_not]
.
[,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/lut_chars/find_if.adoc[find_if]
,
xref:boost/urls/grammar/lut_chars/find_if_not.adoc[find_if_not]
,
xref:boost/urls/grammar/parse-02.adoc[parse]
,
xref:boost/urls/grammar/token_rule.adoc[token_rule]
.



