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Alias template format
Alias template wformat

Header: proxy.h
Module: proxy
Namespace: pro::inline v4::skills
Since: 4.0.0

template <class FB>
using format = /* see below */;

template <class FB>
using wformat = /* see below */;

The alias templates format and wformat modify a specialization of basic_facade_builder to allow formatting via the standard formatting functions. Specializations of std::formatter<proxy_indirect_accessor<F>, char> and std::formatter<proxy_indirect_accessor<F>, wchar_t> will be enabled for the 2 skills, respectively, where F is a built facade type.

format and wformat also add constraints to a built facade type F, requiring a contained value of proxy<F> be formattable. Formally, let p be a contained value of proxy<F>, CharT be char (for format) or wchar_t (for wformat), T be std::decay_t<decltype(*std::as_const(p))>, std::formatter<T, CharT> shall be an enabled specialization of std::formatter.

Example

#include <format>
#include <iostream>

#include <proxy/proxy.h>

struct Formattable : pro::facade_builder              //
                     ::add_skill<pro::skills::format> //
                     ::build {};

int main() {
  pro::proxy<Formattable> p = pro::make_proxy<Formattable>(123);
  std::cout << std::format("{}", *p) << "\n";     // Prints "123"
  std::cout << std::format("{:*<6}", *p) << "\n"; // Prints "123***"
}

See Also