From Jason Turner

[class.pre]

C++23 → Trunk 5.0 KB 51 lines
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Markdown: C++23 | Trunk
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  1. tmp/tmpddgqn_9m/{from.md → to.md} +30 -16
tmp/tmpddgqn_9m/{from.md → to.md} RENAMED
@@ -18,22 +18,29 @@ class-specifier:
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  class-head '{' member-specificationₒₚₜ '}'
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  ```
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  ``` bnf
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  class-head:
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- class-key attribute-specifier-seqₒₚₜ class-head-name class-virt-specifierₒₚₜ base-clauseₒₚₜ
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  class-key attribute-specifier-seqₒₚₜ base-clauseₒₚₜ
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  ```
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  ``` bnf
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  class-head-name:
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  nested-name-specifierₒₚₜ class-name
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  ```
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  ``` bnf
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- class-virt-specifier:
 
 
 
 
 
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  final
 
 
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  ```
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  ``` bnf
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  class-key:
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  class
@@ -43,22 +50,22 @@ class-key:
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  A class declaration where the *class-name* in the *class-head-name* is a
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  *simple-template-id* shall be an explicit specialization
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  [[temp.expl.spec]] or a partial specialization [[temp.spec.partial]]. A
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  *class-specifier* whose *class-head* omits the *class-head-name* defines
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- an unnamed class.
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  [*Note 1*: An unnamed class thus can’t be `final`. — *end note*]
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  Otherwise, the *class-name* is an *identifier*; it is not looked up, and
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  the *class-specifier* introduces it.
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- The *class-name* is also bound in the scope of the class (template)
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- itself; this is known as the *injected-class-name*. For purposes of
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- access checking, the injected-class-name is treated as if it were a
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- public member name. A *class-specifier* is commonly referred to as a
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- *class definition*. A class is considered defined after the closing
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  brace of its *class-specifier* has been seen even though its member
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  functions are in general not yet defined. The optional
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  *attribute-specifier-seq* appertains to the class; the attributes in the
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  *attribute-specifier-seq* are thereafter considered attributes of the
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  class whenever it is named.
@@ -90,38 +97,45 @@ template<> struct A<void> {}; // OK
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  [*Note 2*: The *class-key* determines whether the class is a union
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  [[class.union]] and whether access is public or private by default
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  [[class.access]]. A union holds the value of at most one data member at
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  a time. — *end note*]
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- If a class is marked with the *class-virt-specifier* `final` and it
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- appears as a *class-or-decltype* in a *base-clause* [[class.derived]],
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- the program is ill-formed. Whenever a *class-key* is followed by a
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- *class-head-name*, the *identifier* `final`, and a colon or left brace,
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- `final` is interpreted as a *class-virt-specifier*.
 
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  [*Example 2*:
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  ``` cpp
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  struct A;
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  struct A final {}; // OK, definition of struct A,
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  // not value-initialization of variable final
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  struct X {
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  struct C { constexpr operator int() { return 5; } };
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- struct B final : C{}; // OK, definition of nested class B,
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- // not declaration of a bit-field member final
 
 
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  };
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  ```
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  — *end example*]
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  [*Note 3*: Complete objects of class type have nonzero size. Base class
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  subobjects and members declared with the `no_unique_address` attribute
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  [[dcl.attr.nouniqueaddr]] are not so constrained. — *end note*]
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  [*Note 4*: Class objects can be assigned
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- [[over.ass]], [[class.copy.assign]], passed as arguments to functions
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  [[dcl.init]], [[class.copy.ctor]], and returned by functions (except
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  objects of classes for which copying or moving has been restricted; see 
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  [[dcl.fct.def.delete]] and [[class.access]]). Other plausible operators,
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  such as equality comparison, can be defined by the user; see 
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  [[over.oper]]. — *end note*]
 
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  class-head '{' member-specificationₒₚₜ '}'
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  ```
20
 
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  ``` bnf
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  class-head:
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+ class-key attribute-specifier-seqₒₚₜ class-head-name class-property-specifier-seqₒₚₜ base-clauseₒₚₜ
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  class-key attribute-specifier-seqₒₚₜ base-clauseₒₚₜ
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  ```
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  ``` bnf
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  class-head-name:
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  nested-name-specifierₒₚₜ class-name
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  ```
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  ``` bnf
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+ class-property-specifier-seq:
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+ class-property-specifier class-property-specifier-seqₒₚₜ
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+ ```
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+
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+ ``` bnf
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+ class-property-specifier:
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  final
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+ trivially_relocatable_if_eligible
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+ replaceable_if_eligible
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  ```
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  ``` bnf
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  class-key:
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  class
 
50
 
51
  A class declaration where the *class-name* in the *class-head-name* is a
52
  *simple-template-id* shall be an explicit specialization
53
  [[temp.expl.spec]] or a partial specialization [[temp.spec.partial]]. A
54
  *class-specifier* whose *class-head* omits the *class-head-name* defines
55
+ an *unnamed class*.
56
 
57
  [*Note 1*: An unnamed class thus can’t be `final`. — *end note*]
58
 
59
  Otherwise, the *class-name* is an *identifier*; it is not looked up, and
60
  the *class-specifier* introduces it.
61
 
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+ The component name of the *class-name* is also bound in the scope of the
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+ class (template) itself; this is known as the *injected-class-name*. For
64
+ purposes of access checking, the injected-class-name is treated as if it
65
+ were a public member name. A *class-specifier* is commonly referred to
66
+ as a *class definition*. A class is considered defined after the closing
67
  brace of its *class-specifier* has been seen even though its member
68
  functions are in general not yet defined. The optional
69
  *attribute-specifier-seq* appertains to the class; the attributes in the
70
  *attribute-specifier-seq* are thereafter considered attributes of the
71
  class whenever it is named.
 
97
  [*Note 2*: The *class-key* determines whether the class is a union
98
  [[class.union]] and whether access is public or private by default
99
  [[class.access]]. A union holds the value of at most one data member at
100
  a time. — *end note*]
101
 
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+ Each *class-property-specifier* shall appear at most once within a
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+ single *class-property-specifier-seq*. Whenever a *class-key* is
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+ followed by a *class-head-name*, one of the identifiers `final`,
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+ `trivially_relocatable_if_eligible`, or `replaceable_if_eligible`, and a
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+ colon or left brace, the identifier is interpreted as a
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+ *class-property-specifier*.
108
 
109
  [*Example 2*:
110
 
111
  ``` cpp
112
  struct A;
113
  struct A final {}; // OK, definition of struct A,
114
  // not value-initialization of variable final
115
 
116
  struct X {
117
  struct C { constexpr operator int() { return 5; } };
118
+ struct B trivially_relocatable_if_eligible : C{};
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+ // OK, definition of nested class B,
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+ // not declaration of a bit-field member
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+ // trivially_relocatable_if_eligible
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  };
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  ```
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  — *end example*]
126
 
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+ If a class is marked with the *class-property-specifier* `final` and
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+ that class appears as a *class-or-decltype* in a *base-clause*
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+ [[class.derived]], the program is ill-formed.
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+
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  [*Note 3*: Complete objects of class type have nonzero size. Base class
132
  subobjects and members declared with the `no_unique_address` attribute
133
  [[dcl.attr.nouniqueaddr]] are not so constrained. — *end note*]
134
 
135
  [*Note 4*: Class objects can be assigned
136
+ [[over.assign]], [[class.copy.assign]], passed as arguments to functions
137
  [[dcl.init]], [[class.copy.ctor]], and returned by functions (except
138
  objects of classes for which copying or moving has been restricted; see 
139
  [[dcl.fct.def.delete]] and [[class.access]]). Other plausible operators,
140
  such as equality comparison, can be defined by the user; see 
141
  [[over.oper]]. — *end note*]