basic_facade_builder::add_skill
Since: 4.0.0
template <template <class> class Skill>
requires(/* see below */)
using add_skill = Skill<basic_facade_builder>;
The alias template add_skill modifies template paratemeters with a custom skill. The expression inside requires is equivalent to Skill<basic_facade_builder> is a specialization of basic_facade_builder.
Notes
The implementation of Skill can combine other member alias templates defined in basic_facade_builder as a skillset.
Example
#include <iostream>
#include <proxy/proxy.h>
template <class FB>
using SharedSlim = typename FB //
::template restrict_layout<sizeof(void*), alignof(void*)> //
::template support_copy<pro::constraint_level::nothrow> //
::template add_skill<pro::skills::as_weak>;
struct SharedFormattable : pro::facade_builder //
::add_skill<SharedSlim> //
::add_skill<pro::skills::format> //
::build {};
int main() {
// Raw pointer does not have shared semantics
static_assert(!pro::proxiable<int*, SharedFormattable>);
// The implementation of std::shared_ptr is usually larger than sizeof(void*)
static_assert(!pro::proxiable<std::shared_ptr<int>, SharedFormattable>);
// The built-in shared pointer is guaranteed to be "slim"
pro::proxy<SharedFormattable> p1 =
pro::make_proxy_shared<SharedFormattable>(123);
pro::weak_proxy<SharedFormattable> p2 = p1;
pro::proxy<SharedFormattable> p3 = p2.lock();
std::cout << std::format("{}\n", *p3); // Prints "123"
}