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[meta.reflection.annotation] Move to before [meta.reflection.extract] #8279

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228 changes: 114 additions & 114 deletions source/meta.tex
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Original file line number Diff line number Diff line change
Expand Up @@ -3080,6 +3080,10 @@
consteval size_t alignment_of(info r);
consteval size_t bit_size_of(info r);

// \ref{meta.reflection.annotation}, annotation queries
consteval vector<info> annotations_of(info item);
consteval vector<info> annotations_of_with_type(info item, info type);

// \ref{meta.reflection.extract}, value extraction
template<class T>
consteval T extract(info);
Expand Down Expand Up @@ -3279,10 +3283,6 @@
consteval info variant_alternative(size_t index, info type);

consteval strong_ordering type_order(info type_a, info type_b);

// \ref{meta.reflection.annotation}, annotation reflection
consteval vector<info> annotations_of(info item);
consteval vector<info> annotations_of_with_type(info item, info type);
}
\end{codeblock}

Expand Down Expand Up @@ -5840,6 +5840,116 @@
\end{itemize}
\end{itemdescr}

\rSec2[meta.reflection.annotation]{Annotation queries}

\indexlibraryglobal{annotations_of}%
\begin{itemdecl}
consteval vector<info> annotations_of(info item);
\end{itemdecl}

\begin{itemdescr}
\pnum
Let $E$ be
\begin{itemize}
\item
the corresponding \grammarterm{base-specifier}
if \tcode{item} represents a direct base class relationship,
\item
otherwise, the entity represented by \tcode{item}.
\end{itemize}

\pnum
\returns
A \tcode{vector} containing all of the reflections $R$
representing each annotation applying to each declaration of $E$ that precedes either
some point in the evaluation context\iref{expr.const} or
a point immediately following the \grammarterm{class-specifier}
of the outermost class for which such a point is in a complete-class context.
For any two reflections $R_1$ and $R_2$ in the returned \tcode{vector},
if the annotation represented by $R_1$ precedes the annotation represented by $R_2$,
then $R_1$ appears before $R_2$.
If $R_1$ and $R_2$ represent annotations from the same translation unit $T$,
any element in the returned \tcode{vector} between $R_1$ and $R_2$
represents an annotation from $T$.
\begin{note}
The order in which two annotations appear is otherwise unspecified.
\end{note}
\begin{example}
\begin{codeblock}
[[=1]] void f();
[[=2, =3]] void g();
void g [[=4]] ();

static_assert(annotations_of(^^f).size() == 1);
static_assert(annotations_of(^^g).size() == 3);
static_assert([: constant_of(annotations_of(^^g)[0]) :] == 2);
static_assert(extract<int>(annotations_of(^^g)[1]) == 3);
static_assert(extract<int>(annotations_of(^^g)[2]) == 4);

struct Option { bool value; };

struct C {
[[=Option{true}]] int a;
[[=Option{false}]] int b;
};

static_assert(extract<Option>(annotations_of(^^C::a)[0]).value);
static_assert(!extract<Option>(annotations_of(^^C::b)[0]).value);

template<class T>
struct [[=42]] D { };

constexpr std::meta::info a1 = annotations_of(^^D<int>)[0];
constexpr std::meta::info a2 = annotations_of(^^D<char>)[0];
static_assert(a1 != a2);
static_assert(constant_of(a1) == constant_of(a2));

[[=1]] int x, y;
static_assert(annotations_of(^^x)[0] == annotations_of(^^y)[0]);
\end{codeblock}
\end{example}

\pnum
\throws
\tcode{meta::exception} unless
\tcode{item} represents a
type,
type alias,
variable,
function,
namespace,
enumerator,
direct base class relationship, or
non-static data member.
\end{itemdescr}

\indexlibraryglobal{annotations_of_with_type}%
\begin{itemdecl}
consteval vector<info> annotations_of_with_type(info item, info type);
\end{itemdecl}

\begin{itemdescr}
\pnum
\returns
A \tcode{vector} containing each element \tcode{e} of \tcode{annotations_of(item)}
where
\begin{codeblock}
remove_const(type_of(e)) == remove_const(type)
\end{codeblock}
is \tcode{true}, preserving their order.

\pnum
\throws
\tcode{meta::exception} unless
\begin{itemize}
\item
\tcode{annotations_of(item)} is a constant expression and
\item
\tcode{dealias(type)} represents a type that is complete
from some point in the evaluation context.
\end{itemize}
\end{itemdescr}

\rSec2[meta.reflection.extract]{Value extraction}

\pnum
Expand Down Expand Up @@ -6925,116 +7035,6 @@
represented by \tcode{dealias(t1)} and \tcode{dealias(t2)}, respectively.
\end{itemdescr}

\rSec2[meta.reflection.annotation]{Annotation reflection}

\indexlibraryglobal{annotations_of}%
\begin{itemdecl}
consteval vector<info> annotations_of(info item);
\end{itemdecl}

\begin{itemdescr}
\pnum
Let $E$ be
\begin{itemize}
\item
the corresponding \grammarterm{base-specifier}
if \tcode{item} represents a direct base class relationship,
\item
otherwise, the entity represented by \tcode{item}.
\end{itemize}

\pnum
\returns
A \tcode{vector} containing all of the reflections $R$
representing each annotation applying to each declaration of $E$ that precedes either
some point in the evaluation context\iref{expr.const} or
a point immediately following the \grammarterm{class-specifier}
of the outermost class for which such a point is in a complete-class context.
For any two reflections $R_1$ and $R_2$ in the returned \tcode{vector},
if the annotation represented by $R_1$ precedes the annotation represented by $R_2$,
then $R_1$ appears before $R_2$.
If $R_1$ and $R_2$ represent annotations from the same translation unit $T$,
any element in the returned \tcode{vector} between $R_1$ and $R_2$
represents an annotation from $T$.
\begin{note}
The order in which two annotations appear is otherwise unspecified.
\end{note}
\begin{example}
\begin{codeblock}
[[=1]] void f();
[[=2, =3]] void g();
void g [[=4]] ();

static_assert(annotations_of(^^f).size() == 1);
static_assert(annotations_of(^^g).size() == 3);
static_assert([: constant_of(annotations_of(^^g)[0]) :] == 2);
static_assert(extract<int>(annotations_of(^^g)[1]) == 3);
static_assert(extract<int>(annotations_of(^^g)[2]) == 4);

struct Option { bool value; };

struct C {
[[=Option{true}]] int a;
[[=Option{false}]] int b;
};

static_assert(extract<Option>(annotations_of(^^C::a)[0]).value);
static_assert(!extract<Option>(annotations_of(^^C::b)[0]).value);

template<class T>
struct [[=42]] D { };

constexpr std::meta::info a1 = annotations_of(^^D<int>)[0];
constexpr std::meta::info a2 = annotations_of(^^D<char>)[0];
static_assert(a1 != a2);
static_assert(constant_of(a1) == constant_of(a2));

[[=1]] int x, y;
static_assert(annotations_of(^^x)[0] == annotations_of(^^y)[0]);
\end{codeblock}
\end{example}

\pnum
\throws
\tcode{meta::exception} unless
\tcode{item} represents a
type,
type alias,
variable,
function,
namespace,
enumerator,
direct base class relationship, or
non-static data member.
\end{itemdescr}

\indexlibraryglobal{annotations_of_with_type}%
\begin{itemdecl}
consteval vector<info> annotations_of_with_type(info item, info type);
\end{itemdecl}

\begin{itemdescr}
\pnum
\returns
A \tcode{vector} containing each element \tcode{e} of \tcode{annotations_of(item)}
where
\begin{codeblock}
remove_const(type_of(e)) == remove_const(type)
\end{codeblock}
is \tcode{true}, preserving their order.

\pnum
\throws
\tcode{meta::exception} unless
\begin{itemize}
\item
\tcode{annotations_of(item)} is a constant expression and
\item
\tcode{dealias(type)} represents a type that is complete
from some point in the evaluation context.
\end{itemize}
\end{itemdescr}

\rSec1[ratio]{Compile-time rational arithmetic}

\rSec2[ratio.general]{General}
Expand Down