[template.bitset.general] Break out 'bitset::reference' into its own subclause

This change is consistent with specification of nested classes
elsewhere in the standard, and allows better use of qualified
names in the declaration of member functions in their own
specification.

Author: AlisdairM

source/utilities.tex

@@ -10533,22 +10533,8 @@
 namespace std {
   template<size_t N> class bitset {
   public:
-    // bit reference
-    class reference {
-    public:
-      constexpr reference(const reference& x) noexcept;
-      constexpr ~reference();
-      constexpr reference& operator=(bool x) noexcept;              // for \tcode{b[i] = x;}
-      constexpr reference& operator=(const reference& x) noexcept;  // for \tcode{b[i] = b[j];}
-      constexpr const reference& operator=(bool x) const noexcept;
-      constexpr operator bool() const noexcept;                     // for \tcode{x = b[i];}
-      constexpr bool operator~() const noexcept;                    // flips the bit
-      constexpr reference& flip() noexcept;                         // for \tcode{b[i].flip();}
-
-      friend constexpr void swap(reference x, reference y) noexcept;
-      friend constexpr void swap(reference x, bool& y) noexcept;
-      friend constexpr void swap(bool& x, reference y) noexcept;
-    };
+    // \ref{bitset.reference}, bit reference
+    class reference;
 
     // \ref{bitset.cons}, constructors
     constexpr bitset() noexcept;
@@ -10625,6 +10611,8 @@
 \tcode{bitset<N>}
 describes an object that can store a sequence consisting of a fixed number of
 bits, \tcode{N}.
+The class \tcode{bitset<N>::reference} simulates a reference
+to a single bit in the sequence.
 
 \pnum
 Each bit represents either the value zero (reset) or one (set).
@@ -10644,12 +10632,55 @@
 or more bits is the sum of their bit values.
 
 \pnum
-\tcode{reference}
-is a class that simulates a reference to a single bit in the sequence.
+The functions described in \ref{template.bitset} can report three kinds of
+errors, each associated with a distinct exception:
+\begin{itemize}
+\item
+an
+\term{invalid-argument}
+error is associated with exceptions of type
+\tcode{invalid_argument}\iref{invalid.argument};
+\indexlibraryglobal{invalid_argument}%
+\item
+an
+\term{out-of-range}
+error is associated with exceptions of type
+\tcode{out_of_range}\iref{out.of.range};
+\indexlibraryglobal{out_of_range}%
+\item
+an
+\term{overflow}
+error is associated with exceptions of type
+\tcode{overflow_error}\iref{overflow.error}.
+\indexlibraryglobal{overflow_error}%
+\end{itemize}
+
+\rSec3[bitset.reference]{Class \tcode{bitset<N>::reference}}%
+\indexlibrarymember{reference}{bitset}%
+\begin{codeblock}
+namespace std {
+  template<size_t N>
+  class bitset<N>::reference {
+  public:
+    constexpr reference(const reference& x) noexcept;
+    constexpr ~reference();
+    constexpr reference& operator=(bool x) noexcept;                // for \tcode{b[i] = x;}
+    constexpr reference& operator=(const reference& x) noexcept;    // for \tcode{b[i] = b[j];}
+    constexpr const reference& operator=(bool x) const noexcept;
+    constexpr operator bool() const noexcept;                       // for \tcode{x = b[i];}
+    constexpr bool operator~() const noexcept;                      // flips the bit
+    constexpr reference& flip() noexcept;                           // for \tcode{b[i].flip();}
+
+    friend constexpr void swap(reference x, reference y) noexcept;
+    friend constexpr void swap(reference x, bool& y) noexcept;
+    friend constexpr void swap(bool& x, reference y) noexcept;
+  };
+}
+\end{codeblock}
 
 \indexlibraryctor{bitset::reference}%
 \begin{itemdecl}
-constexpr reference::reference(const reference& x) noexcept;
+constexpr reference(const reference& x) noexcept;
 \end{itemdecl}
 
 \begin{itemdescr}
@@ -10660,7 +10691,7 @@
 
 \indexlibrarydtor{bitset::reference}%
 \begin{itemdecl}
-constexpr reference::~reference();
+constexpr ~reference();
 \end{itemdecl}
 
 \begin{itemdescr}
@@ -10671,9 +10702,9 @@
 
 \indexlibrarymember{operator=}{bitset::reference}%
 \begin{itemdecl}
-constexpr reference& reference::operator=(bool x) noexcept;
-constexpr reference& reference::operator=(const reference& x) noexcept;
-constexpr const reference& reference::operator=(bool x) const noexcept;
+constexpr reference& operator=(bool x) noexcept;
+constexpr reference& operator=(const reference& x) noexcept;
+constexpr const reference& operator=(bool x) const noexcept;
 \end{itemdecl}
 
 \begin{itemdescr}
@@ -10687,6 +10718,21 @@
 \tcode{*this}.
 \end{itemdescr}
 
+\indexlibrarymember{flip}{bitset::reference}%
+\begin{itemdecl}
+constexpr reference& flip() noexcept;
+\end{itemdecl}
+
+\begin{itemdescr}
+\pnum
+\effects
+Equivalent to \tcode{*this = !*this}.
+
+\pnum
+\returns
+\tcode{*this}.
+\end{itemdescr}
+
 \indexlibrarymember{swap}{bitset::reference}%
 \begin{itemdecl}
 constexpr void swap(reference x, reference y) noexcept;
@@ -10706,45 +10752,6 @@
 \end{codeblock}
 \end{itemdescr}
 
-\indexlibrarymember{flip}{bitset::reference}%
-\begin{itemdecl}
-constexpr reference& reference::flip() noexcept;
-\end{itemdecl}
-
-\begin{itemdescr}
-\pnum
-\effects
-Equivalent to \tcode{*this = !*this}.
-
-\pnum
-\returns
-\tcode{*this}.
-\end{itemdescr}
-
-\pnum
-The functions described in \ref{template.bitset} can report three kinds of
-errors, each associated with a distinct exception:
-\begin{itemize}
-\item
-an
-\term{invalid-argument}
-error is associated with exceptions of type
-\tcode{invalid_argument}\iref{invalid.argument};
-\indexlibraryglobal{invalid_argument}%
-\item
-an
-\term{out-of-range}
-error is associated with exceptions of type
-\tcode{out_of_range}\iref{out.of.range};
-\indexlibraryglobal{out_of_range}%
-\item
-an
-\term{overflow}
-error is associated with exceptions of type
-\tcode{overflow_error}\iref{overflow.error}.
-\indexlibraryglobal{overflow_error}%
-\end{itemize}
-
 \rSec3[bitset.cons]{Constructors}
 
 \indexlibraryctor{bitset}%