From Jason Turner

[temp.variadic]

C++11 → C++14 3.6 KB 41 lines
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Archived: C++11 | C++14
Markdown: C++11 | C++14
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  1. tmp/tmp25kp9qu8/{from.md → to.md} +26 -10
tmp/tmp25kp9qu8/{from.md → to.md} RENAMED
@@ -43,12 +43,13 @@ the following contexts:
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  *type-parameter* without the ellipsis.
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  - In an *initializer-list* ([[dcl.init]]); the pattern is an
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  *initializer-clause*.
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  - In a *base-specifier-list* (Clause  [[class.derived]]); the pattern is
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  a *base-specifier*.
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- - In a *mem-initializer-list* ([[class.base.init]]); the pattern is a
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- *mem-initializer*.
 
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  - In a *template-argument-list* ([[temp.arg]]); the pattern is a
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  *template-argument*.
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  - In a *dynamic-exception-specification* ([[except.spec]]); the pattern
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  is a *type-id*.
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  - In an *attribute-list* ([[dcl.attr.grammar]]); the pattern is an
@@ -58,10 +59,15 @@ the following contexts:
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  - In a *capture-list* ([[expr.prim.lambda]]); the pattern is a
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  *capture*.
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  - In a `sizeof...` expression ([[expr.sizeof]]); the pattern is an
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  *identifier*.
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  ``` cpp
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  template<class ... Types> void f(Types ... rest);
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  template<class ... Types> void g(Types ... rest) {
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  f(&rest ...); // ``&rest ...'' is a pack expansion; ``&rest'' is its pattern
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  }
@@ -105,18 +111,28 @@ template<class ... Args>
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  The instantiation of a pack expansion that is not a `sizeof...`
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  expression produces a list
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  $\mathtt{E}_1, \mathtt{E}_2, ..., \mathtt{E}_N$, where N is the number
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  of elements in the pack expansion parameters. Each Eᵢ is generated by
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  instantiating the pattern and replacing each pack expansion parameter
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- with its ith element. All of the Eᵢ become elements in the enclosing
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- list. The variety of list varies with the context: *expression-list*,
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- *base-specifier-list*, *template-argument-list*, etc. When N is zero,
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- the instantiation of the expansion produces an empty list. Such an
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- instantiation does not alter the syntactic interpretation of the
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- enclosing construct, even in cases where omitting the list entirely
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- would otherwise be ill-formed or would result in an ambiguity in the
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- grammar.
 
 
 
 
 
 
 
 
 
 
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  ``` cpp
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  template<class... T> struct X : T... { };
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  template<class... T> void f(T... values) {
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  X<T...> x(values...);
 
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  *type-parameter* without the ellipsis.
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  - In an *initializer-list* ([[dcl.init]]); the pattern is an
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  *initializer-clause*.
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  - In a *base-specifier-list* (Clause  [[class.derived]]); the pattern is
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  a *base-specifier*.
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+ - In a *mem-initializer-list* ([[class.base.init]]) for a
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+ *mem-initializer* whose *mem-initializer-id* denotes a base class; the
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+ pattern is the *mem-initializer*.
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  - In a *template-argument-list* ([[temp.arg]]); the pattern is a
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  *template-argument*.
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  - In a *dynamic-exception-specification* ([[except.spec]]); the pattern
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  is a *type-id*.
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  - In an *attribute-list* ([[dcl.attr.grammar]]); the pattern is an
 
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  - In a *capture-list* ([[expr.prim.lambda]]); the pattern is a
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  *capture*.
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  - In a `sizeof...` expression ([[expr.sizeof]]); the pattern is an
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  *identifier*.
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+ For the purpose of determining whether a parameter pack satisfies a rule
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+ regarding entities other than parameter packs, the parameter pack is
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+ considered to be the entity that would result from an instantiation of
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+ the pattern in which it appears.
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+
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  ``` cpp
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  template<class ... Types> void f(Types ... rest);
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  template<class ... Types> void g(Types ... rest) {
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  f(&rest ...); // ``&rest ...'' is a pack expansion; ``&rest'' is its pattern
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  }
 
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  The instantiation of a pack expansion that is not a `sizeof...`
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  expression produces a list
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  $\mathtt{E}_1, \mathtt{E}_2, ..., \mathtt{E}_N$, where N is the number
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  of elements in the pack expansion parameters. Each Eᵢ is generated by
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  instantiating the pattern and replacing each pack expansion parameter
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+ with its ith element. Such an element, in the context of the
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+ instantiation, is interpreted as follows:
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+
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+ - if the pack is a template parameter pack, the element is a template
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+ parameter ([[temp.param]]) of the corresponding kind (type or
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+ non-type) designating the type or value from the template argument;
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+ otherwise,
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+ - if the pack is a function parameter pack, the element is an
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+ *id-expression* designating the function parameter that resulted from
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+ the instantiation of the pattern where the pack is declared.
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+
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+ All of the Eᵢ become elements in the enclosing list. The variety of list
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+ varies with the context: *expression-list*, *base-specifier-list*,
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+ *template-argument-list*, etc. When N is zero, the instantiation of the
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+ expansion produces an empty list. Such an instantiation does not alter
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+ the syntactic interpretation of the enclosing construct, even in cases
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+ where omitting the list entirely would otherwise be ill-formed or would
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+ result in an ambiguity in the grammar.
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  ``` cpp
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  template<class... T> struct X : T... { };
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  template<class... T> void f(T... values) {
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  X<T...> x(values...);