A set of composable and partially-applicable function objects to simplify the use of algorithms and views

namespace svw = std::views;
namespace srg = std::ranges;

struct box
{
    std::string label;
    float weight;
};

struct store
{
    store(auto) {}
};

auto boxes = std::vector<box>{...};
std::ranges::sort(boxes, brun::less_equal);

auto heavy = boxes | svw::filter(boxes, brun::greater_equal(10), &box::weight);
auto my_boxes = heavy | svw::filter(heavy, brun::equals("Joe"), &box::label);
auto take_stuff = my_boxes | svw::transform(brun::minus(10), &box::weight);
auto store_all = take_stuff | svw::transform(brun::construct<store>);

Bit operators:

• bit_and
• bit_or
• bit_xor
• bit_not

Functional:

• apply
• compose
• identity
• construct<T>, construct<T>.from_tuple
• get<N>
• at(N), at[N]

Equality and ordering:

• equal_to
• not_equal_to
• less
• less_equal
• greater
• greater_equal

Arithmetic:

• plus
• minus
• multiplies
• divides
• negate

All bit, arithmetic, equality and ordering operators have a member .tuple that accepts a tuple and computes the operation on its members. For example: static_assert(plus.tuple(std::pair{2, 3}) == 5)