fixup: add upto 34.9.11.9

Author: jensmaurer

source/exec.tex

@@ -3487,6 +3487,93 @@
 propagates the other completion operations sent by \tcode{sndr}.
 \end{itemize}
 
+\rSec3[exec.bulk]{\tcode{execution::bulk}}
+
+\pnum
+\tcode{bulk} runs a task repeatedly for every index in an index space.
+
+The name \tcode{bulk} denotes a pipeable sender adaptor object.
+For subexpressions \tcode{sndr}, \tcode{shape}, and \tcode{f},
+let \tcode{Shape} be \tcode{decltype(auto(shape))}.
+If
+\begin{itemize}
+\item
+\tcode{decltype((sndr))} does not satisfy \libconcept{sender}, or
+\item
+\tcode{Shape} does not satisfy \libconcept{integral}, or
+\item
+\tcode{decltype((f))} does not satisfy \exposconcept{movable-value},
+\end{itemize}
+\tcode{bulk(sndr, shape, f)} is ill-formed.
+
+\pnum
+Otherwise,
+the expression \tcode{bulk(sndr, shape, f)} is expression-equivalent to:
+
+\begin{codeblock}
+transform_sender(@\exposid{get-domain-early}@(sndr), @\exposid{make-sender}@(bulk, @\exposid{product-type}@{shape, f}, sndr))
+\end{codeblock}
+except that \tcode{sndr} is evaluated only once.
+
+\pnum
+The exposition-only class template \exposid{impls-for}\iref{exec.snd.general}
+is specialized for \tcode{bulk_t} as follows:
+\begin{codeblock}
+namespace std::execution {
+  template<>
+  struct @\exposid{impls-for}@<bulk_t> : @\exposid{default-impls}@ {
+    static constexpr auto @\exposid{complete}@ = @\seebelow@;
+  };
+}
+\end{codeblock}
+
+\pnum
+The member \tcode{\exposid{impls-for}<bulk_t>::\exposid{complete}}
+is initialized with a callable object equivalent to the following lambda:
+\begin{codeblock}
+[]<class Index, class State, class Rcvr, class Tag, class... Args>
+  (Index, State& state, Rcvr& rcvr, Tag, Args&&... args) noexcept -> void requires @\seebelow@ {
+    if constexpr (@\libconcept{same_as}@<Tag, set_value_t>) {
+      auto& [shape, f] = state;
+      constexpr bool nothrow = noexcept(f(auto(shape), args...));
+      @\exposid{TRY-EVAL}@(rcvr, [&]() noexcept(nothrow) {
+        for (decltype(auto(shape)) i = 0; i < shape; ++i) {
+          f(auto(i), args...);
+        }
+        Tag()(std::move(rcvr), std::forward<Args>(args)...);
+      }());
+    } else {
+      Tag()(std::move(rcvr), std::forward<Args>(args)...);
+    }
+  }
+\end{codeblock}
+
+\pnum
+The expression in the \grammarterm{requires-clause} of the lambda above
+is \tcode{true} if and only
+if \tcode{Tag} denotes a type other than \tcode{set_value_t} or
+if the expression \tcode{f(auto(shape), args...)} is well-formed.
+
+\pnum
+Let the subexpression \tcode{out_sndr} denote
+the result of the invocation \tcode{bulk(sndr, shape, f)} or
+an object equal to such, and
+let the subexpression \tcode{rcvr} denote a receiver
+such that the expression \tcode{connect(out_sndr, rcvr)} is well-formed.
+The expression \tcode{connect(out_sndr, rcvr)} has undefined behavior
+unless it creates an asynchronous operation\iref{exec.async.ops} that,
+when started,
+\begin{itemize}
+\item
+on a value completion operation,
+invokes \tcode{f(i, args...)}
+for every \tcode{i} of type \tcode{Shape} from \tcode{0} to \tcode{shape},
+where \tcode{args} is a pack of lvalue subexpressions
+referring to the value completion result datums of the input sender, and
+\item
+propagates all completion operations sent by \tcode{sndr}.
+\end{itemize}
+
 \rSec1[exec.util]{Sender/receiver utilities}