21 Metaprogramming library [meta]

21.4 Reflection [meta.reflection]

21.4.14 Promoting to static storage arrays [meta.reflection.array]

The functions in this subclause promote compile-time storage into static storage.

template<ranges::input_range R>
  consteval info reflect_constant_string(R&& r);

Let CharT be ranges::range_value_t<R>.

Mandates: CharT is one of char, wchar_t, char8_t, char16_t, char32_t.

Let V be the pack of values of type CharT whose elements are the corresponding elements of r, except that if r refers to a string literal object, then V does not include the trailing null terminator of r.

Let P be the template parameter object ([temp.param]) of type const CharT[sizeof...(V)+1] initialized with V..., CHART().

Returns: ^^P.

[Note 1:

P is a potentially non-unique object ([intro.object]).

— end note]

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template<ranges::input_range R>
  consteval info reflect_constant_array(R&& r);

Let T be ranges::range_value_t<R>.

Mandates: T is a structural type ([temp.param]), is_constructible_v<T, ranges::range_reference_t<R>> is true, and is_copy_constructible_v<T> is true.

Constant When: reflect_constant(e) is a constant subexpression for every element e of r.

Let V be the pack of values of type info of the same size as r, where the

i^{th}

element is reflect_constant(

e_{i}

), where

e_{i}

is the

i^{th}

element of r.

Let P be

(12.1)
If sizeof...(V) > 0 is true, then the template parameter object ([temp.param]) of type const T[sizeof...(V)] initialized with {[:V:]...}.
(12.2)
Otherwise, the template parameter object of type array<T, 0> initialized with {}.

Returns: ^^P.

[Note 2:

P is a potentially non-unique object ([intro.object]).

— end note]