Skip to content

fix the attributes of sequence and repeat algorithms #1922

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
ericniebler merged 4 commits into from
Mar 11, 2026
+725 −503
Merged

fix the attributes of sequence and repeat algorithms #1922

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
677c647
fix the attributes of `sequence` and `repeat` algorithms
ericniebler Mar 11, 2026
96e6a76
work around gcc bug
ericniebler Mar 11, 2026
25adb8d
workarounds for nvc++ bugs
ericniebler Mar 11, 2026
6e72620
add missing #include
ericniebler Mar 11, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
62 changes: 35 additions & 27 deletions include/exec/repeat_n.hpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,9 @@ STDEXEC_PRAGMA_IGNORE_GNU("-Wunused-value")

namespace experimental::execution
{
struct repeat_n_t;
struct _THE_INPUT_SENDER_MUST_HAVE_VOID_VALUE_COMPLETION_;

namespace __repeat_n
{
using namespace STDEXEC;
Expand All @@ -50,9 +53,8 @@ namespace experimental::execution
virtual constexpr void __cleanup() noexcept = 0;
virtual constexpr void __repeat() noexcept = 0;

_Receiver __rcvr_;
std::size_t __count_;
trampoline_scheduler __sched_{};
_Receiver __rcvr_;
std::size_t __count_;

protected:
~__opstate_base() noexcept = default;
Expand Down Expand Up @@ -109,8 +111,13 @@ namespace experimental::execution
__result_of<exec::sequence, schedule_result_t<trampoline_scheduler>, _Child &>;
using __child_op_t = STDEXEC::connect_result_t<__bouncy_sndr_t, __receiver_t>;

static constexpr bool __nothrow_connect =
__nothrow_invocable<STDEXEC::schedule_t, trampoline_scheduler>
&& __nothrow_invocable<sequence_t, schedule_result_t<trampoline_scheduler>, _Child &>
&& __nothrow_connectable<__bouncy_sndr_t, __receiver_t>;

constexpr explicit __opstate(std::size_t __count, _Child __child, _Receiver __rcvr)
noexcept(__nothrow_move_constructible<_Child> && noexcept(__connect()))
noexcept(__nothrow_move_constructible<_Child> && __nothrow_connect)
: __opstate_base<_Receiver>{static_cast<_Receiver &&>(__rcvr), __count}
, __child_(std::move(__child))
{
Expand All @@ -132,13 +139,10 @@ namespace experimental::execution
}
}

constexpr auto __connect() noexcept(
__nothrow_invocable<STDEXEC::schedule_t, trampoline_scheduler &>
&& __nothrow_invocable<sequence_t, schedule_result_t<trampoline_scheduler>, _Child &>
&& __nothrow_connectable<__bouncy_sndr_t, __receiver_t>) -> __child_op_t &
constexpr auto __connect() noexcept(__nothrow_connect) -> __child_op_t &
{
return __child_op_.__emplace_from(STDEXEC::connect,
exec::sequence(STDEXEC::schedule(this->__sched_),
exec::sequence(STDEXEC::schedule(trampoline_scheduler{}),
__child_),
__receiver_t{this});
}
Expand All @@ -165,7 +169,7 @@ namespace experimental::execution
}
STDEXEC_CATCH_ALL
{
if constexpr (!noexcept(__connect()))
if constexpr (!__nothrow_connect)
{
STDEXEC::set_error(std::move(this->__rcvr_), std::current_exception());
}
Expand All @@ -180,9 +184,6 @@ namespace experimental::execution
STDEXEC_HOST_DEVICE_DEDUCTION_GUIDE
__opstate(std::size_t, _Child, _Receiver) -> __opstate<_Child, _Receiver>;

struct repeat_n_t;
struct _THE_INPUT_SENDER_MUST_HAVE_VOID_VALUE_COMPLETION_;

template <class _Child, class... _Args>
using __values_t =
// There's something funny going on with __if_c here. Use std::conditional_t instead. :-(
Expand Down Expand Up @@ -215,6 +216,13 @@ namespace experimental::execution

struct __impls : __sexpr_defaults
{
static constexpr auto __get_attrs =
[]<class _Child>(__ignore, __ignore, _Child const &__child) noexcept
-> __seq::__attrs<schedule_result_t<trampoline_scheduler>, _Child &>
{
return {STDEXEC::schedule(trampoline_scheduler{}), const_cast<_Child &>(__child)};
};

template <class _Sender, class... _Env>
static consteval auto __get_completion_signatures()
{
Expand All @@ -232,24 +240,24 @@ namespace experimental::execution
static_cast<_Receiver &&>(__rcvr));
};
};
} // namespace __repeat_n

struct repeat_n_t
struct repeat_n_t
{
template <STDEXEC::sender _Sender>
constexpr auto operator()(_Sender &&__sndr, std::size_t __count) const //
-> STDEXEC::__well_formed_sender auto
{
template <sender _Sender>
constexpr auto operator()(_Sender &&__sndr, std::size_t __count) const
{
return __make_sexpr<repeat_n_t>(__count, static_cast<_Sender &&>(__sndr));
}
return STDEXEC::__make_sexpr<repeat_n_t>(__count, static_cast<_Sender &&>(__sndr));
}

STDEXEC_ATTRIBUTE(always_inline)
constexpr auto operator()(std::size_t __count) const noexcept
{
return __closure(*this, __count);
}
};
} // namespace __repeat_n
STDEXEC_ATTRIBUTE(always_inline)
constexpr auto operator()(std::size_t __count) const noexcept
{
return STDEXEC::__closure(*this, __count);
}
};

using __repeat_n::repeat_n_t;
inline constexpr repeat_n_t repeat_n{};
} // namespace experimental::execution

Expand Down
Loading
Loading