From: dgregor_at_[hidden]
Date: 2008-08-24 22:49:46
Author: dgregor
Date: 2008-08-24 22:49:45 EDT (Sun, 24 Aug 2008)
New Revision: 48366
URL: http://svn.boost.org/trac/boost/changeset/48366
Log:
Specify how one handles the 'initialization of an object' case when instantiating a call to an associated function
Text files modified:
sandbox/committee/concepts/wording/wording.tex | 56 +++++++++++++++++++++++++++++++++++++--
1 files changed, 53 insertions(+), 3 deletions(-)
Modified: sandbox/committee/concepts/wording/wording.tex
==============================================================================
--- sandbox/committee/concepts/wording/wording.tex (original)
+++ sandbox/committee/concepts/wording/wording.tex 2008-08-24 22:49:45 EDT (Sun, 24 Aug 2008)
@@ -109,6 +109,24 @@
\begin{itemize}
\item Removed the deprecation of \tcode{late_check}.
+\item Clarified how a ``call to an associated function candidate set''
+ actually works in the \techterm{pseudo-destructor-name} and
+ ``initialization of an object'' cases
+ (\ref{temp.constrained.inst}). For example:
+\begin{codeblock}
+auto concept DefaultConstructible<typename T> {
+ T::T();
+}
+
+template<DefaultConstructible T>
+void f() {
+ T t1; // type-checks as a call to \tcode{DefaultConstructible<T>}'s \tcode{T::T()}
+ T t2{}; // type-checks as a call to \tcode{DefaultConstructible<T>}'s \tcode{T::T()}
+}
+
+template void f<int>(); // \tcode{t1} is not initialized, \tcode{t2} is value-initialized
+\end{codeblock}
+
\item The \tcode{MoveConstructible<T>} requirement is no longer
propagated from the types of function parameters
(\ref{temp.req.impl}). This change brings concepts in sync with
@@ -6262,10 +6280,18 @@
\addedConcepts{In the instantiation of a constrained template, a call
to a function that resolves to an associated
function in a concept map archetype (\mbox{\ref{temp.archetype}})
- will be instantiated as a call to the associated function candidate set
+ will be instantiated} \changedCCC{as a call to}{using}
+\addedConcepts{the associated function candidate set
(\mbox{\ref{temp.constrained.set}}) that satisfies the
corresponding associated function requirement in the concept map
- that replaces the concept map archetype. \mbox{\enterexample}}
+ that replaces the concept map archetype.}
+\addedCC{The instantiated form depends on the seed of the associated
+ function candidate set and the syntactic form that resulted in the
+ call in the constrained template:}
+\begin{itemize}
+\additemCC{if the seed is a function, the instantiated form is a call
+ to the associated function candidate set.}
+\addedConcepts{\mbox{\enterexample}}
\begin{codeblock}
concept F<typename T> {
T::T();
@@ -6288,7 +6314,31 @@
g(x);
}
\end{codeblock}
-\exitexample\
+\addedConcepts{\exitexample}
+
+\additemCC{if the seed is a \mbox{\techterm{pseudo-destructor-name}},
+ the instantiated form is a pseudo destructor call
+ (\mbox{\ref{expr.pseudo}}).}
+
+\additemCC{if the seed is the initialization of an object, the
+ instantiated form is the appropriate kind of initialization (or no
+ initialization) based on
+ the syntactic form in the constrained template. \enterexample}
+\begin{codeblock}
+auto concept DefaultConstructible<typename T> {
+ T::T();
+}
+
+template<DefaultConstructible T>
+void f() {
+ T t1; // type-checks as a call to \tcode{DefaultConstructible<T>}'s \tcode{T::T()}
+ T t2{}; // type-checks as a call to \tcode{DefaultConstructible<T>}'s \tcode{T::T()}
+}
+
+template void f<int>(); // \tcode{t1} is not initialized, \tcode{t2} is value-initialized
+\end{codeblock}
+\addedCC{\exitexample}
+\end{itemize}
\pnum
\addedConcepts{A function template specialization in a constrained