Merge 2024-03 CWG Motion 4

P0609R3 Attributes for Structured Bindings

Author: tkoeppe

source/declarations.tex

@@ -67,11 +67,27 @@
     \keyword{using} identifier \opt{attribute-specifier-seq} \terminal{=} defining-type-id \terminal{;}
 \end{bnf}
 
+\begin{bnf}
+\nontermdef{attributed-identifier}\br
+    identifier \opt{attribute-specifier-seq}
+\end{bnf}
+
+\begin{bnf}
+\nontermdef{attributed-identifier-list}\br
+    attributed-identifier\br
+    attributed-identifier-list \terminal{,} attributed-identifier
+\end{bnf}
+
+\begin{bnf}
+\nontermdef{structured-binding-declaration}\br
+    \opt{attribute-specifier-seq} decl-specifier-seq \opt{ref-qualifier} \terminal{[} attributed-identifier-list \terminal{]}
+\end{bnf}
+
 \begin{bnf}
 \nontermdef{simple-declaration}\br
     decl-specifier-seq \opt{init-declarator-list} \terminal{;}\br
     attribute-specifier-seq decl-specifier-seq init-declarator-list \terminal{;}\br
-    \opt{attribute-specifier-seq} decl-specifier-seq \opt{ref-qualifier} \terminal{[} identifier-list \terminal{]} initializer \terminal{;}
+    structured-binding-declaration initializer \terminal{;}
 \end{bnf}
 
 \begin{bnf}
@@ -186,7 +202,7 @@
 \end{example}
 
 \pnum
-A \grammarterm{simple-declaration} with an \grammarterm{identifier-list} is called
+A \grammarterm{simple-declaration} with a \grammarterm{structured-binding-declaration} is called
 a \defn{structured binding declaration}\iref{dcl.struct.bind}.
 Each \grammarterm{decl-specifier} in the \grammarterm{decl-specifier-seq}
 shall be
@@ -6968,8 +6984,11 @@
 A structured binding declaration introduces the \grammarterm{identifier}{s}
 $\tcode{v}_0$, $\tcode{v}_1$, $\tcode{v}_2, \dotsc$
 of the
-\grammarterm{identifier-list} as names
+\grammarterm{attributed-identifier-list} as names
 of \defn{structured binding}{s}.
+The optional \grammarterm{attribute-specifier-seq} of
+an \grammarterm{attributed-identifier}
+appertains to the structured binding so introduced.
 Let \cv{} denote the \grammarterm{cv-qualifier}{s} in
 the \grammarterm{decl-specifier-seq} and
 \placeholder{S} consist of the \grammarterm{storage-class-specifier}{s} of
@@ -7008,7 +7027,7 @@
 
 \pnum
 If \tcode{E} is an array type with element type \tcode{T}, the number
-of elements in the \grammarterm{identifier-list} shall be equal to the
+of elements in the \grammarterm{attributed-identifier-list} shall be equal to the
 number of elements of \tcode{E}. Each $\tcode{v}_i$ is the name of an
 lvalue that refers to the element $i$ of the array and whose type
 is \tcode{T}; the referenced type is \tcode{T}.
@@ -7031,7 +7050,7 @@
 shall be a well-formed integral constant expression
 and
 the number of elements in
-the \grammarterm{identifier-list} shall be equal to the value of that
+the \grammarterm{attributed-identifier-list} shall be equal to the value of that
 expression.
 Let \tcode{i} be an index prvalue of type \tcode{std::size_t}
 corresponding to $\tcode{v}_i$.
@@ -7073,7 +7092,7 @@
 well-formed when named as \tcode{\exposidnc{e}.\placeholder{name}}
 in the context of the structured binding,
 \tcode{E} shall not have an anonymous union member, and
-the number of elements in the \grammarterm{identifier-list} shall be
+the number of elements in the \grammarterm{attributed-identifier-list} shall be
 equal to the number of non-static data members of \tcode{E}.
 Designating the non-static data members of \tcode{E} as
 $\tcode{m}_0$, $\tcode{m}_1$, $\tcode{m}_2, \dotsc$
@@ -9246,6 +9265,7 @@
 The attribute may be applied to the declaration of a class,
 \grammarterm{typedef-name},
 variable (including a structured binding declaration),
+structured binding,
 non-static data member,
 function,
 enumeration, or

source/preprocessor.tex

@@ -1868,7 +1868,7 @@
 \defnxname{cpp_sized_deallocation}                & \tcode{201309L} \\ \rowsep
 \defnxname{cpp_static_assert}                     & \tcode{202306L} \\ \rowsep
 \defnxname{cpp_static_call_operator}              & \tcode{202207L} \\ \rowsep
-\defnxname{cpp_structured_bindings}               & \tcode{201606L} \\ \rowsep
+\defnxname{cpp_structured_bindings}               & \tcode{202403L} \\ \rowsep
 \defnxname{cpp_template_template_args}            & \tcode{201611L} \\ \rowsep
 \defnxname{cpp_threadsafe_static_init}            & \tcode{200806L} \\ \rowsep
 \defnxname{cpp_unicode_characters}                & \tcode{200704L} \\ \rowsep

source/statements.tex

@@ -509,7 +509,7 @@
 \begin{bnf}
 \nontermdef{for-range-declaration}\br
     \opt{attribute-specifier-seq} decl-specifier-seq declarator\br
-    \opt{attribute-specifier-seq} decl-specifier-seq \opt{ref-qualifier} \terminal{[} identifier-list \terminal{]}
+    structured-binding-declaration
 \end{bnf}
 
 \begin{bnf}