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All the row operations: best::{tlist, row}::{at, join, push, insert, splice, remove, erase, gather, scatter} #12

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merged 12 commits into from
Jun 24, 2024
Merged

All the row operations: best::{tlist, row}::{at, join, push, insert, splice, remove, erase, gather, scatter} #12

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4fc8859
add scatter/gather to tlist
mcy Jun 23, 2024
ea25a0e
add nodiscard warnings to tlist
mcy Jun 23, 2024
7ac8d09
implement row::join()
mcy Jun 23, 2024
dd871ef
add row::at(range)
mcy Jun 24, 2024
a24caf7
add row::splice() and friends
mcy Jun 24, 2024
142d4ab
shift arguments around
mcy Jun 24, 2024
d5d865c
add row::gather and row::scatter
mcy Jun 24, 2024
d6ee90f
cleanup
mcy Jun 24, 2024
af63271
rename best::row_forward to best::fwd
mcy Jun 24, 2024
e20cb36
changed my mind
mcy Jun 24, 2024
d4cb75b
get rid of random calls to .fotward()
mcy Jun 24, 2024
7a0b722
get rid of random calls to .fotward()
mcy Jun 24, 2024
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add row::at(range)
  • Loading branch information
@mcy
mcy committed Jun 24, 2024
commit dd871ef664c36effbb2a0f92ddfcb5ce1de98d01
25 changes: 24 additions & 1 deletion best/container/internal/row.h
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Original file line number Diff line number Diff line change
Expand Up @@ -125,9 +125,32 @@ template <size_t... i, typename... Elems>
struct impl<const best::vlist<i...>, Elems...>
: best::ebo<best::object<Elems>, Elems, i>... {};

// See tlist_internal::slice_impl().
using ::best::tlist_internal::splat;
template <typename Out, size_t... i, size_t... j, size_t... k>
constexpr auto make_slicer(std::index_sequence<i...>, std::index_sequence<j...>,
std::index_sequence<k...>) {
return []<splat<i>... prefix, splat<j>... infix, splat<k>... suffix>(
prefix&&..., infix&&... args, suffix&&...) {
return Out{BEST_FWD(args)...};
};
}
template <best::bounds b, typename... Ts,
auto count = b.try_compute_count(sizeof...(Ts))>
requires(count.has_value())
constexpr auto slice(auto&& row) {
using Out = decltype(row.types.template at<b>().template apply<best::row>());
return BEST_FWD(row).apply([](auto&&... args) {
return make_slicer<Out>(
std::make_index_sequence<b.start>{}, std::make_index_sequence<*count>{},
std::make_index_sequence<sizeof...(args) - (b.start + *count)>{})(
BEST_FWD(args)...);
});
}

// See tlist_internal::join().
using ::best::tlist_internal::fast_nth;
using ::best::tlist_internal::join_lut;

constexpr auto join(auto&&... those) {
return [&]<auto... i>(best::vlist<i...>) {
auto rowrow = best::row{best::bind, BEST_FWD(those)...};
Expand Down
97 changes: 73 additions & 24 deletions best/container/row.h
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Original file line number Diff line number Diff line change
Expand Up @@ -177,24 +177,33 @@ class row final
/// Returns whether this is the empty row `best::row<>`.
constexpr static bool is_empty() { return types.size() == 0; }

/// # `row[index<n>]`
/// # `row[index<n>]`, `row[best::values<bounds{...}>]`
///
/// Returns the `n`th element.
/// Returns a reference to the `n`th element, or a subrange as a row (values
/// are copied/moved as appropriate).
// clang-format off
template <size_t n> constexpr cref<n> operator[](best::index_t<n> idx) const&;
template <size_t n> constexpr ref<n> operator[](best::index_t<n> idx) &;
template <size_t n> constexpr crref<n> operator[](best::index_t<n> idx) const&&;
template <size_t n> constexpr rref<n> operator[](best::index_t<n> idx) &&;
template <size_t n> constexpr cref<n> operator[](best::index_t<n>) const&;
template <size_t n> constexpr ref<n> operator[](best::index_t<n>) &;
template <size_t n> constexpr crref<n> operator[](best::index_t<n>) const&&;
template <size_t n> constexpr rref<n> operator[](best::index_t<n>) &&;
template <best::bounds range> constexpr auto operator[](best::vlist<range>) const&;
template <best::bounds range> constexpr auto operator[](best::vlist<range>) &;
template <best::bounds range> constexpr auto operator[](best::vlist<range>) const&&;
template <best::bounds range> constexpr auto operator[](best::vlist<range>) &&;
// clang-format on

/// # `row::at(index<n>)`
/// # `row::at(index<n>)`, `row::at(best::values<bounds{...}>)`
///
/// Identical to `operator[]` in all ways.
// clang-format off
template <size_t n> constexpr cref<n> at(best::index_t<n> = {}) const&;
template <size_t n> constexpr ref<n> at(best::index_t<n> = {}) &;
template <size_t n> constexpr crref<n> at(best::index_t<n> = {}) const&&;
template <size_t n> constexpr rref<n> at(best::index_t<n> = {}) &&;
template <best::bounds range> constexpr auto at(best::vlist<range> = {}) const&;
template <best::bounds range> constexpr auto at(best::vlist<range> = {}) &;
template <best::bounds range> constexpr auto at(best::vlist<range> = {}) const&&;
template <best::bounds range> constexpr auto at(best::vlist<range> = {}) &&;
// clang-format on

/// # `row::object(index<n>)`
Expand Down Expand Up @@ -232,22 +241,6 @@ class row final
template <typename T> constexpr decltype(auto) select(best::tlist<T> idx = {}) &&;
// clang-format on

/// # `tlist::join()`, `tlist::operator+`
///
/// Concatenates several rows with this one.
///
/// This is also made available via `operator+`, but beware: using a fold with
/// `operator+` here is quadratic; you should generally prefer `join()` for
/// variadic cases.
constexpr auto join(best::is_row auto&&...) const&;
constexpr auto join(best::is_row auto&&...) &;
constexpr auto join(best::is_row auto&&...) const&&;
constexpr auto join(best::is_row auto&&...) &&;
constexpr auto operator+(best::is_row auto&&) const&;
constexpr auto operator+(best::is_row auto&&) &;
constexpr auto operator+(best::is_row auto&&) const&&;
constexpr auto operator+(best::is_row auto&&) &&;

/// # `row::first()`, `row::second()`, `row::last()`
///
/// Gets the first, second, or last value; helper for `std::pair`-like uses.
Expand All @@ -266,6 +259,22 @@ class row final
constexpr decltype(auto) last() && requires (!types.is_empty());
// clang-format on

/// # `tlist::join()`, `tlist::operator+`
///
/// Concatenates several rows with this one.
///
/// This is also made available via `operator+`, but beware: using a fold with
/// `operator+` here is quadratic; you should generally prefer `join()` for
/// variadic cases.
constexpr auto join(best::is_row auto&&...) const&;
constexpr auto join(best::is_row auto&&...) &;
constexpr auto join(best::is_row auto&&...) const&&;
constexpr auto join(best::is_row auto&&...) &&;
constexpr auto operator+(best::is_row auto&&) const&;
constexpr auto operator+(best::is_row auto&&) &;
constexpr auto operator+(best::is_row auto&&) const&&;
constexpr auto operator+(best::is_row auto&&) &&;

/// # `row::apply()`
///
/// Calls `f` with a pack of references of the elements of this tuple.
Expand Down Expand Up @@ -418,6 +427,27 @@ constexpr row<A...>::rref<n> row<A...>::operator[](best::index_t<n> idx) && {
return static_cast<best::as_rref<T>>(*static_cast<B&>(*this).get());
}

template <typename... A>
template <best::bounds range>
constexpr auto row<A...>::operator[](best::vlist<range>) const& {
return row_internal::slice<range, A...>(*this);
}
template <typename... A>
template <best::bounds range>
constexpr auto row<A...>::operator[](best::vlist<range>) & {
return row_internal::slice<range, A...>(*this);
}
template <typename... A>
template <best::bounds range>
constexpr auto row<A...>::operator[](best::vlist<range>) const&& {
return row_internal::slice<range, A...>(BEST_MOVE(*this));
}
template <typename... A>
template <best::bounds range>
constexpr auto row<A...>::operator[](best::vlist<range>) && {
return row_internal::slice<range, A...>(BEST_MOVE(*this));
}

template <typename... A>
template <size_t n>
constexpr row<A...>::cref<n> row<A...>::at(best::index_t<n> idx) const& {
Expand Down Expand Up @@ -447,7 +477,26 @@ constexpr row<A...>::rref<n> row<A...>::at(best::index_t<n> idx) && {
using B = best::ebo<best::object<T>, T, n>;
return static_cast<best::as_rref<T>>(*static_cast<B&>(*this).get());
}

template <typename... A>
template <best::bounds range>
constexpr auto row<A...>::at(best::vlist<range>) const& {
return row_internal::slice<range, A...>(*this);
}
template <typename... A>
template <best::bounds range>
constexpr auto row<A...>::at(best::vlist<range>) & {
return row_internal::slice<range, A...>(*this);
}
template <typename... A>
template <best::bounds range>
constexpr auto row<A...>::at(best::vlist<range>) const&& {
return row_internal::slice<range, A...>(BEST_MOVE(*this));
}
template <typename... A>
template <best::bounds range>
constexpr auto row<A...>::at(best::vlist<range>) && {
return row_internal::slice<range, A...>(BEST_MOVE(*this));
}
template <typename... A>
template <size_t n>
constexpr const best::object<typename row<A...>::template type<n>>&
Expand Down
10 changes: 10 additions & 0 deletions best/container/row_test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -99,4 +99,14 @@ best::test Join = [](auto& t) {
best::row<MoveOnly> x2 = BEST_MOVE(x1) + best::row();
x2 = best::row() + BEST_MOVE(x1);
};

best::test Slice = [](auto& t) {
best::row<int, long, int*, int> x0{1, 2, nullptr, 4};
t.expect_eq(x0.at<bounds{.count = 2}>(), best::row{1, 2});
t.expect_eq(x0.at<bounds{.start = 2}>(), best::row{nullptr, 4});
t.expect_eq(x0.at<bounds{.start = 2, .count = 0}>(), best::row{});

best::row x1{MoveOnly(), 42};
BEST_MOVE(x1).at<bounds{.start = 0, .count = 1}>();
};
} // namespace best::row_test