...

common/adc_traits.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <ranges>
 #include <tuple>
 #include <type_traits>
 
@@ -14,6 +15,10 @@
 namespace adc::traits
 {
 
+// range of char/const char
+template <typename R>
+concept adc_char_range = std::ranges::range<R> && std::is_same_v<std::remove_cv_t<std::ranges::range_value_t<R>>, char>;
+
 // deduce returned type of callable
 template <typename T>
 using adc_retval_t = std::invoke_result_t<std::remove_cvref_t<T>>;
@@ -74,7 +79,7 @@ using adc_deduced_type =
 
 // perfect-forwarding wrapper
 template <typename T, typename... Ts>
-auto adc_pf_wrapper(T&& v, Ts&&... vs)
+constexpr static auto adc_pf_wrapper(T&& v, Ts&&... vs)
 {
     return std::tuple<adc_deduced_type<T>, adc_deduced_type<Ts>...>(std::forward<T>(v), std::forward<Ts>(vs)...);
 }