diff mbox series

libstdc++: Implement P2540R1 change to views::cartesian_product()

Message ID 20240116143818.3336042-1-ppalka@redhat.com
State New
Headers show
Series libstdc++: Implement P2540R1 change to views::cartesian_product() | expand

Commit Message

Patrick Palka Jan. 16, 2024, 2:38 p.m. UTC
Tested on x86_64-pc-linux-gnu, does this look OK for trunk/13?

-- >8 --

This paper changes the identity element of views::cartesian_product to
be a single empty tuple instead of an empty range.

libstdc++-v3/ChangeLog:

	* include/std/ranges (views::_CartesianProduct::operator()):
	Adjust identity case as per P2540R1.
	* testsuite/std/ranges/cartesian_product/1.cc (test01):
	Adjust expected result of the identity case.
---
 libstdc++-v3/include/std/ranges                          | 2 +-
 libstdc++-v3/testsuite/std/ranges/cartesian_product/1.cc | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

Comments

Jonathan Wakely Jan. 16, 2024, 2:41 p.m. UTC | #1
On Tue, 16 Jan 2024 at 14:39, Patrick Palka wrote:
>
> Tested on x86_64-pc-linux-gnu, does this look OK for trunk/13?

Oh! I thought this went in as part of the original cartesian_product
commit. I would have asked you to do it at the same time otherwise,
sorry.

Yes, OK for trunk and gcc-13, thanks.


>
> -- >8 --
>
> This paper changes the identity element of views::cartesian_product to
> be a single empty tuple instead of an empty range.
>
> libstdc++-v3/ChangeLog:
>
>         * include/std/ranges (views::_CartesianProduct::operator()):
>         Adjust identity case as per P2540R1.
>         * testsuite/std/ranges/cartesian_product/1.cc (test01):
>         Adjust expected result of the identity case.
> ---
>  libstdc++-v3/include/std/ranges                          | 2 +-
>  libstdc++-v3/testsuite/std/ranges/cartesian_product/1.cc | 6 +++---
>  2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
> index 3135e6f0c08..7ef835f486a 100644
> --- a/libstdc++-v3/include/std/ranges
> +++ b/libstdc++-v3/include/std/ranges
> @@ -8748,7 +8748,7 @@ namespace views::__adaptor
>         operator() [[nodiscard]] (_Ts&&... __ts) const
>         {
>           if constexpr (sizeof...(_Ts) == 0)
> -           return views::empty<tuple<>>;
> +           return views::single(tuple{});
>           else
>             return cartesian_product_view<all_t<_Ts>...>(std::forward<_Ts>(__ts)...);
>         }
> diff --git a/libstdc++-v3/testsuite/std/ranges/cartesian_product/1.cc b/libstdc++-v3/testsuite/std/ranges/cartesian_product/1.cc
> index f69f965c0ce..7281cd8a2f4 100644
> --- a/libstdc++-v3/testsuite/std/ranges/cartesian_product/1.cc
> +++ b/libstdc++-v3/testsuite/std/ranges/cartesian_product/1.cc
> @@ -24,9 +24,9 @@ test01()
>    int w[] = {9};
>
>    auto v0 = views::cartesian_product();
> -  VERIFY( ranges::end(v0) - ranges::begin(v0) == 0 );
> -  VERIFY( ranges::size(v0) == 0 );
> -  VERIFY( ranges::empty(v0) );
> +  VERIFY( ranges::end(v0) - ranges::begin(v0) == 1 );
> +  VERIFY( ranges::size(v0) == 1 );
> +  VERIFY( !ranges::empty(v0) );
>
>    auto v1 = views::cartesian_product(x);
>    VERIFY( ranges::end(v1) - ranges::begin(v1) == 3 );
> --
> 2.43.0.334.gd4dbce1db5
>
Patrick Palka Jan. 16, 2024, 2:49 p.m. UTC | #2
On Tue, 16 Jan 2024, Jonathan Wakely wrote:

> On Tue, 16 Jan 2024 at 14:39, Patrick Palka wrote:
> >
> > Tested on x86_64-pc-linux-gnu, does this look OK for trunk/13?
> 
> Oh! I thought this went in as part of the original cartesian_product
> commit. I would have asked you to do it at the same time otherwise,
> sorry.
> 
> Yes, OK for trunk and gcc-13, thanks.

Thanks, and sorry for letting this slip through the cracks.  I made
sure to include relevant LWG issue resolutions as part of the original
commit, but I managed to miss this paper.

> 
> 
> >
> > -- >8 --
> >
> > This paper changes the identity element of views::cartesian_product to
> > be a single empty tuple instead of an empty range.
> >
> > libstdc++-v3/ChangeLog:
> >
> >         * include/std/ranges (views::_CartesianProduct::operator()):
> >         Adjust identity case as per P2540R1.
> >         * testsuite/std/ranges/cartesian_product/1.cc (test01):
> >         Adjust expected result of the identity case.
> > ---
> >  libstdc++-v3/include/std/ranges                          | 2 +-
> >  libstdc++-v3/testsuite/std/ranges/cartesian_product/1.cc | 6 +++---
> >  2 files changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
> > index 3135e6f0c08..7ef835f486a 100644
> > --- a/libstdc++-v3/include/std/ranges
> > +++ b/libstdc++-v3/include/std/ranges
> > @@ -8748,7 +8748,7 @@ namespace views::__adaptor
> >         operator() [[nodiscard]] (_Ts&&... __ts) const
> >         {
> >           if constexpr (sizeof...(_Ts) == 0)
> > -           return views::empty<tuple<>>;
> > +           return views::single(tuple{});
> >           else
> >             return cartesian_product_view<all_t<_Ts>...>(std::forward<_Ts>(__ts)...);
> >         }
> > diff --git a/libstdc++-v3/testsuite/std/ranges/cartesian_product/1.cc b/libstdc++-v3/testsuite/std/ranges/cartesian_product/1.cc
> > index f69f965c0ce..7281cd8a2f4 100644
> > --- a/libstdc++-v3/testsuite/std/ranges/cartesian_product/1.cc
> > +++ b/libstdc++-v3/testsuite/std/ranges/cartesian_product/1.cc
> > @@ -24,9 +24,9 @@ test01()
> >    int w[] = {9};
> >
> >    auto v0 = views::cartesian_product();
> > -  VERIFY( ranges::end(v0) - ranges::begin(v0) == 0 );
> > -  VERIFY( ranges::size(v0) == 0 );
> > -  VERIFY( ranges::empty(v0) );
> > +  VERIFY( ranges::end(v0) - ranges::begin(v0) == 1 );
> > +  VERIFY( ranges::size(v0) == 1 );
> > +  VERIFY( !ranges::empty(v0) );
> >
> >    auto v1 = views::cartesian_product(x);
> >    VERIFY( ranges::end(v1) - ranges::begin(v1) == 3 );
> > --
> > 2.43.0.334.gd4dbce1db5
> >
> 
>
diff mbox series

Patch

diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index 3135e6f0c08..7ef835f486a 100644
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -8748,7 +8748,7 @@  namespace views::__adaptor
 	operator() [[nodiscard]] (_Ts&&... __ts) const
 	{
 	  if constexpr (sizeof...(_Ts) == 0)
-	    return views::empty<tuple<>>;
+	    return views::single(tuple{});
 	  else
 	    return cartesian_product_view<all_t<_Ts>...>(std::forward<_Ts>(__ts)...);
 	}
diff --git a/libstdc++-v3/testsuite/std/ranges/cartesian_product/1.cc b/libstdc++-v3/testsuite/std/ranges/cartesian_product/1.cc
index f69f965c0ce..7281cd8a2f4 100644
--- a/libstdc++-v3/testsuite/std/ranges/cartesian_product/1.cc
+++ b/libstdc++-v3/testsuite/std/ranges/cartesian_product/1.cc
@@ -24,9 +24,9 @@  test01()
   int w[] = {9};
 
   auto v0 = views::cartesian_product();
-  VERIFY( ranges::end(v0) - ranges::begin(v0) == 0 );
-  VERIFY( ranges::size(v0) == 0 );
-  VERIFY( ranges::empty(v0) );
+  VERIFY( ranges::end(v0) - ranges::begin(v0) == 1 );
+  VERIFY( ranges::size(v0) == 1 );
+  VERIFY( !ranges::empty(v0) );
 
   auto v1 = views::cartesian_product(x);
   VERIFY( ranges::end(v1) - ranges::begin(v1) == 3 );