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[exec.snd.expos] Reorder specification immediately after declaration #8322

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[exec.snd.expos] Reorder specification immediately after declaration #8322

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182 changes: 103 additions & 79 deletions source/exec.tex
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Original file line number Diff line number Diff line change
Expand Up @@ -1731,20 +1731,6 @@
concept @\defexposconceptnc{completion-tag}@ = // \expos
@\libconcept{same_as}@<Tag, set_value_t> || @\libconcept{same_as}@<Tag, set_error_t> || @\libconcept{same_as}@<Tag, set_stopped_t>;

struct @\exposidnc{default-impls}@ { // \expos
static constexpr auto @\exposidnc{get-attrs}@ = @\seebelownc@; // \expos
static constexpr auto @\exposidnc{get-env}@ = @\seebelownc@; // \expos
static constexpr auto @\exposidnc{get-state}@ = @\seebelownc@; // \expos
static constexpr auto @\exposidnc{start}@ = @\seebelownc@; // \expos
static constexpr auto @\exposidnc{complete}@ = @\seebelownc@; // \expos

template<class Sndr, class... Env>
static consteval void @\exposidnc{check-types}@(); // \expos
};

template<class Tag>
struct @\exposidnc{impls-for}@ : @\exposidnc{default-impls}@ {}; // \expos

template<class Sndr, class Rcvr> // \expos
using @\exposid{state-type}@ = decay_t<@\exposid{call-result-t}@<
decltype(@\exposid{impls-for}@<tag_of_t<Sndr>>::@\exposid{get-state}@), Sndr, Rcvr&>>;
Expand Down Expand Up @@ -1772,7 +1758,26 @@
Rcvr @\exposidnc{rcvr}@; // \expos
@\exposidnc{state-type}@<Sndr, Rcvr> @\exposidnc{state}@; // \expos
};
}
\end{codeblock}

\pnum
The expression in the \tcode{noexcept} clause of
the constructor of \exposid{basic-state} is
\begin{codeblock}
is_nothrow_move_constructible_v<Rcvr> &&
@\exposconcept{nothrow-callable}@<decltype(@\exposid{impls-for}@<tag_of_t<Sndr>>::@\exposid{get-state}@), Sndr, Rcvr&> &&
(@\libconcept{same_as}@<@\exposid{state-type}@<Sndr, Rcvr>, @\exposid{get-state-result}@> ||
is_nothrow_constructible_v<@\exposid{state-type}@<Sndr, Rcvr>, @\exposid{get-state-result}@>)
\end{codeblock}
where \exposid{get-state-result} is
\begin{codeblock}
@\exposid{call-result-t}@<decltype(@\exposid{impls-for}@<tag_of_t<Sndr>>::@\exposid{get-state}@), Sndr, Rcvr&>.
\end{codeblock}

\pnum
\begin{codeblock}
namespace std::execution {
template<class Sndr, class Rcvr, class Index>
requires @\exposconcept{valid-specialization}@<@\exposid{env-type}@, Index, Sndr, Rcvr>
struct @\exposidnc{basic-receiver}@ { // \expos
Expand Down Expand Up @@ -1805,77 +1810,19 @@

@\exposidnc{basic-state}@<Sndr, Rcvr>* @\exposidnc{op}@; // \expos
};
}
\end{codeblock}

\begin{codeblock}
namespace std::execution {
constexpr auto @\exposidnc{connect-all}@ = @\seebelownc@; // \expos

template<class Sndr, class Rcvr>
using @\exposidnc{connect-all-result}@ = @\exposidnc{call-result-t}@< // \expos
decltype(@\exposid{connect-all}@), @\exposid{basic-state}@<Sndr, Rcvr>*, Sndr, @\exposid{indices-for}@<Sndr>>;

template<class Sndr, class Rcvr>
requires @\exposconcept{valid-specialization}@<@\exposid{state-type}@, Sndr, Rcvr> &&
@\exposconcept{valid-specialization}@<@\exposid{connect-all-result}@, Sndr, Rcvr>
struct @\exposidnc{basic-operation}@ : @\exposidnc{basic-state}@<Sndr, Rcvr> { // \expos
using operation_state_concept = operation_state_t;
using @\exposidnc{tag-t}@ = tag_of_t<Sndr>; // \expos

@\exposidnc{connect-all-result}@<Sndr, Rcvr> @\exposidnc{inner-ops}@; // \expos

@\exposidnc{basic-operation}@(Sndr&& sndr, Rcvr&& rcvr) noexcept(@\seebelownc@) // \expos
: @\exposid{basic-state}@<Sndr, Rcvr>(std::forward<Sndr>(sndr), std::move(rcvr)),
@\exposid{inner-ops}@(@\exposid{connect-all}@(this, std::forward<Sndr>(sndr), @\exposid{indices-for}@<Sndr>()))
{}

void start() & noexcept {
auto& [...ops] = @\exposid{inner-ops}@;
@\exposid{impls-for}@<tag-t>::@\exposid{start}@(this->@\exposid{state}@, this->@\exposid{rcvr}@, ops...);
}
};

template<class Tag, class Data, class... Child>
struct @\exposidnc{basic-sender}@ : @\exposidnc{product-type}@<Tag, Data, Child...> { // \expos
using sender_concept = sender_t;
using @\exposidnc{indices-for}@ = index_sequence_for<Child...>; // \expos

decltype(auto) get_env() const noexcept {
auto& [_, data, ...child] = *this;
return @\exposid{impls-for}@<Tag>::@\exposid{get-attrs}@(data, child...);
}

template<@\exposconcept{decays-to}@<@\exposid{basic-sender}@> Self, @\libconcept{receiver}@ Rcvr>
auto connect(this Self&& self, Rcvr rcvr) noexcept(@\seebelow@)
-> @\exposid{basic-operation}@<Self, Rcvr> {
return {std::forward<Self>(self), std::move(rcvr)};
}

template<@\exposconcept{decays-to}@<@\exposid{basic-sender}@> Self, class... Env>
static constexpr auto get_completion_signatures();
};
}
\end{codeblock}

\pnum
It is unspecified whether a specialization of \exposid{basic-sender}
is an aggregate.

\pnum
An expression of type \exposid{basic-sender} is usable as
the initializer of a structured binding declaration\iref{dcl.struct.bind}.

\pnum
The expression in the \tcode{noexcept} clause of
the constructor of \exposid{basic-state} is
\begin{codeblock}
is_nothrow_move_constructible_v<Rcvr> &&
@\exposconcept{nothrow-callable}@<decltype(@\exposid{impls-for}@<tag_of_t<Sndr>>::@\exposid{get-state}@), Sndr, Rcvr&> &&
(@\libconcept{same_as}@<@\exposid{state-type}@<Sndr, Rcvr>, @\exposid{get-state-result}@> ||
is_nothrow_constructible_v<@\exposid{state-type}@<Sndr, Rcvr>, @\exposid{get-state-result}@>)
\end{codeblock}
where \exposid{get-state-result} is
\begin{codeblock}
@\exposid{call-result-t}@<decltype(@\exposid{impls-for}@<tag_of_t<Sndr>>::@\exposid{get-state}@), Sndr, Rcvr&>.
\end{codeblock}

\pnum
The object \exposid{connect-all} is initialized with
a callable object equivalent to the following lambda:
Expand All @@ -1902,6 +1849,31 @@
otherwise, \tcode{false}.
\end{itemdescr}

\pnum
\begin{codeblock}
namespace std::execution {
template<class Sndr, class Rcvr>
requires @\exposconcept{valid-specialization}@<@\exposid{state-type}@, Sndr, Rcvr> &&
@\exposconcept{valid-specialization}@<@\exposid{connect-all-result}@, Sndr, Rcvr>
struct @\exposidnc{basic-operation}@ : @\exposidnc{basic-state}@<Sndr, Rcvr> { // \expos
using operation_state_concept = operation_state_t;
using @\exposidnc{tag-t}@ = tag_of_t<Sndr>; // \expos

@\exposidnc{connect-all-result}@<Sndr, Rcvr> @\exposidnc{inner-ops}@; // \expos

@\exposidnc{basic-operation}@(Sndr&& sndr, Rcvr&& rcvr) noexcept(@\seebelownc@) // \expos
: @\exposid{basic-state}@<Sndr, Rcvr>(std::forward<Sndr>(sndr), std::move(rcvr)),
@\exposid{inner-ops}@(@\exposid{connect-all}@(this, std::forward<Sndr>(sndr), @\exposid{indices-for}@<Sndr>()))
{}

void start() & noexcept {
auto& [...ops] = @\exposid{inner-ops}@;
@\exposid{impls-for}@<tag-t>::@\exposid{start}@(this->@\exposid{state}@, this->@\exposid{rcvr}@, ops...);
}
};
}
\end{codeblock}

\pnum
The expression in the \tcode{noexcept} clause of
the constructor of \exposid{basic-operation} is:
Expand All @@ -1911,10 +1883,22 @@
\end{codeblock}

\pnum
The expression in the \tcode{noexcept} clause of
the \tcode{connect} member function of \exposid{basic-sender} is:
\begin{codeblock}
is_nothrow_constructible_v<@\exposid{basic-operation}@<Self, Rcvr>, Self, Rcvr>
namespace std::execution {
struct @\exposidnc{default-impls}@ { // \expos
static constexpr auto @\exposidnc{get-attrs}@ = @\seebelownc@; // \expos
static constexpr auto @\exposidnc{get-env}@ = @\seebelownc@; // \expos
static constexpr auto @\exposidnc{get-state}@ = @\seebelownc@; // \expos
static constexpr auto @\exposidnc{start}@ = @\seebelownc@; // \expos
static constexpr auto @\exposidnc{complete}@ = @\seebelownc@; // \expos

template<class Sndr, class... Env>
static consteval void @\exposidnc{check-types}@(); // \expos
};

template<class Tag>
struct @\exposidnc{impls-for}@ : @\exposidnc{default-impls}@ {}; // \expos
}
\end{codeblock}

\pnum
Expand Down Expand Up @@ -2004,6 +1988,46 @@
\end{note}
\end{itemdescr}

\pnum
\begin{codeblock}
namespace std::execution {
template<class Tag, class Data, class... Child>
struct @\exposidnc{basic-sender}@ : @\exposidnc{product-type}@<Tag, Data, Child...> { // \expos
using sender_concept = sender_t;
using @\exposidnc{indices-for}@ = index_sequence_for<Child...>; // \expos

decltype(auto) get_env() const noexcept {
auto& [_, data, ...child] = *this;
return @\exposid{impls-for}@<Tag>::@\exposid{get-attrs}@(data, child...);
}

template<@\exposconcept{decays-to}@<@\exposid{basic-sender}@> Self, @\libconcept{receiver}@ Rcvr>
auto connect(this Self&& self, Rcvr rcvr) noexcept(@\seebelow@)
-> @\exposid{basic-operation}@<Self, Rcvr> {
return {std::forward<Self>(self), std::move(rcvr)};
}

template<@\exposconcept{decays-to}@<@\exposid{basic-sender}@> Self, class... Env>
static constexpr auto get_completion_signatures();
};
}
\end{codeblock}

\pnum
It is unspecified whether a specialization of \exposid{basic-sender}
is an aggregate.

\pnum
An expression of type \exposid{basic-sender} is usable as
the initializer of a structured binding declaration\iref{dcl.struct.bind}.

\pnum
The expression in the \tcode{noexcept} clause of
the \tcode{connect} member function of \exposid{basic-sender} is:
\begin{codeblock}
is_nothrow_constructible_v<@\exposid{basic-operation}@<Self, Rcvr>, Self, Rcvr>
\end{codeblock}

\indexlibrarymember{get_completion_signatures}{\exposid{basic-sender}}%
\begin{itemdecl}
template<class Tag, class Data, class... Child>
Expand Down