Merge 2023-06 LWG Motion 28

P2714R1 Bind front and back to NTTP callables

Author: tkoeppe

source/support.tex

@@ -576,8 +576,8 @@
 #define @\defnlibxname{cpp_lib_atomic_value_initialization}@       201911L // freestanding, also in \libheader{atomic}, \libheader{memory}
 #define @\defnlibxname{cpp_lib_atomic_wait}@                       201907L // freestanding, also in \libheader{atomic}
 #define @\defnlibxname{cpp_lib_barrier}@                           202302L // also in \libheader{barrier}
-#define @\defnlibxname{cpp_lib_bind_back}@                         202202L // freestanding, also in \libheader{functional}
-#define @\defnlibxname{cpp_lib_bind_front}@                        201907L // freestanding, also in \libheader{functional}
+#define @\defnlibxname{cpp_lib_bind_back}@                         202306L // freestanding, also in \libheader{functional}
+#define @\defnlibxname{cpp_lib_bind_front}@                        202306L // freestanding, also in \libheader{functional}
 #define @\defnlibxname{cpp_lib_bit_cast}@                          201806L // freestanding, also in \libheader{bit}
 #define @\defnlibxname{cpp_lib_bitops}@                            201907L // freestanding, also in \libheader{bit}
 #define @\defnlibxname{cpp_lib_bitset}@                            202306L // also in \libheader{bitset}
@@ -704,7 +704,7 @@
 #define @\defnlibxname{cpp_lib_nonmember_container_access}@        201411L
   // freestanding, also in \libheader{array}, \libheader{deque}, \libheader{forward_list}, \libheader{iterator}, \libheader{list}, \libheader{map}, \libheader{regex}, \libheader{set},
   // \libheader{string}, \libheader{unordered_map}, \libheader{unordered_set}, \libheader{vector}
-#define @\defnlibxname{cpp_lib_not_fn}@                            201603L // freestanding, also in \libheader{functional}
+#define @\defnlibxname{cpp_lib_not_fn}@                            202306L // freestanding, also in \libheader{functional}
 #define @\defnlibxname{cpp_lib_null_iterators}@                    201304L // freestanding, also in \libheader{iterator}
 #define @\defnlibxname{cpp_lib_optional}@                          202110L // also in \libheader{optional}
 #define @\defnlibxname{cpp_lib_out_ptr}@                           202106L // also in \libheader{memory}

source/utilities.tex

@@ -10594,12 +10594,17 @@
 
   // \ref{func.not.fn}, function template \tcode{not_fn}
   template<class F> constexpr @\unspec@ not_fn(F&& f);                            // freestanding
+  template<auto f> constexpr @\unspec@ not_fn() noexcept;                         // freestanding
 
   // \ref{func.bind.partial}, function templates \tcode{bind_front} and \tcode{bind_back}
   template<class F, class... Args>
     constexpr @\unspec@ bind_front(F&&, Args&&...);                               // freestanding
+  template<auto f, class... Args>
+    constexpr @\unspec@ bind_front(Args&&...);                                    // freestanding
   template<class F, class... Args>
     constexpr @\unspec@ bind_back(F&&, Args&&...);                                // freestanding
+  template<auto f, class... Args>
+    constexpr @\unspec@ bind_back(Args&&...);                                     // freestanding
 
   // \ref{func.bind}, bind
   template<class T> struct is_bind_expression;                                      // freestanding
@@ -12303,6 +12308,36 @@
 Any exception thrown by the initialization of \tcode{fd}.
 \end{itemdescr}
 
+\indexlibraryglobal{not_fn}%
+\begin{itemdecl}
+template<auto f> constexpr @\unspec@ not_fn() noexcept;
+\end{itemdecl}
+
+\begin{itemdescr}
+\pnum
+In the text that follows:
+\begin{itemize}
+\item
+\tcode{F} is the type of \tcode{f},
+\item
+\tcode{g} is a value of the result of a \tcode{not_fn} invocation,
+\item
+\tcode{call_args} is an argument pack
+used in a function call expression\iref{expr.call} of \tcode{g}.
+\end{itemize}
+
+\pnum
+\mandates
+If \tcode{is_pointer_v<F> || is_member_pointer_v<F>} is \tcode{true},
+then \tcode{f != nullptr} is \tcode{true}.
+
+\pnum
+\returns
+A perfect forwarding call wrapper\iref{func.require} \tcode{g} that
+does not have state entities, and
+has the call pattern \tcode{!invoke(f, call_args...)}.
+\end{itemdescr}
+
 \rSec2[func.bind.partial]{Function templates \tcode{bind_front} and \tcode{bind_back}}
 
 \indexlibraryglobal{bind_front}%
@@ -12371,6 +12406,71 @@
 the initialization of the state entities of \tcode{g}\iref{func.def}.
 \end{itemdescr}
 
+\indexlibraryglobal{bind_front}%
+\indexlibraryglobal{bind_back}%
+\begin{itemdecl}
+template<auto f, class... Args>
+  constexpr @\unspec@ bind_front(Args&&... args);
+template<auto f, class... Args>
+  constexpr @\unspec@ bind_back(Args&&... args);
+\end{itemdecl}
+
+\begin{itemdescr}
+\pnum
+Within this subclause:
+\begin{itemize}
+\item
+\tcode{F} is the type of \tcode{f},
+\item
+\tcode{g} is a value of the result of
+a \tcode{bind_front} or \tcode{bind_back} invocation,
+\item
+\tcode{BoundArgs} is a pack that denotes \tcode{decay_t<Args>...},
+\item
+\tcode{bound_args} is a pack of bound argument entities of
+\tcode{g}\iref{func.def} of types \tcode{BoundArgs...},
+direct-non-list-initialized with \tcode{std::forward<Args>(args)...},
+respectively, and
+\item
+\tcode{call_args} is an argument pack used in
+a function call expression\iref{expr.call} of \tcode{g}.
+\end{itemize}
+
+\pnum
+\mandates
+\begin{itemize}
+\item
+\tcode{(is_constructible_v<BoundArgs, Args> \&\& ...)} is \tcode{true}, and
+\item
+\tcode{(is_move_constructible_v<BoundArgs> \&\& ...)} is \tcode{true}, and
+\item
+if \tcode{is_pointer_v<F> || is_member_pointer_v<F>} is \tcode{true},
+then \tcode{f != nullptr} is \tcode{true}.
+\end{itemize}
+
+\pnum
+\expects
+For each $\tcode{T}_i$ in \tcode{BoundArgs},
+$\tcode{T}_i$ meets the \oldconcept{MoveConstructible} requirements.
+
+\pnum
+\returns
+A perfect forwarding call wrapper\iref{func.require} \tcode{g} that
+does not have a target object, and has the call pattern:
+\begin{itemize}
+\item
+\tcode{invoke(f, bound_args..., call_args...)}
+for a \tcode{bind_front} invocation, or
+\item
+\tcode{invoke(f, call_args..., bound_args...)}
+for a \tcode{bind_back} invocation.
+\end{itemize}
+
+\pnum
+throws
+Any exception thrown by the initialization of \tcode{bound_args}.
+\end{itemdescr}
+
 \rSec2[func.bind]{Function object binders}%
 
 \rSec3[func.bind.general]{General}%