The set of all letters.

Synopsis

Defined in header <boost/url/grammar/alpha_chars.hpp>

constexpr implementation-defined alpha_chars;

Example

Character sets are used with rules and the functions find_if and find_if_not.

result< string_view > rv = parse( "JohnDoe", token_rule( alpha_chars ) );

BNF

ALPHA       = %x41-5A / %x61-7A
            ; A-Z / a-z

Specification

See Also

find_if, find_if_not, parse, token_rule.

Convenience header <boost/url/grammar.hpp>