cpp/named req/Formatter

is a type that abstracts formatting operations for a given formatting argument type and character type. Specializations of std provided by the standard library are required to meet the requirements of except as noted otherwise.

A is able to format both const and non-const arguments, typically by providing a  member function that takes a const reference.

Requirements
A type satisfies if it satisfies  and given
 * , a formatting argument type
 * , a character type
 * , a type for types  and
 * , a type
 * , a value of type (possibly const)
 * , a value of type
 * , an lvalue of type
 * , a value of type convertible to (possibly const)
 * , an alias of
 * , an alias of
 * , an lvalue of type
 * , an lvalue of type