A modern C++ metaprogramming library. It provides high level algorithms to manipulate heterogeneous sequences, allows writing type-level computations with a natural syntax, provides tools to introspect user-defined types and much more
Your standard library for metaprogramming
Overview
#include <boost/hana.hpp>
#include <cassert>
#include <string>
namespace hana = boost::hana;
using namespace hana::literals;
struct Fish { std::string name; };
struct Cat { std::string name; };
struct Dog { std::string name; };
int main() {
// Sequences capable of holding heterogeneous objects, and algorithms
// to manipulate them.
auto animals = hana::make_tuple(Fish{"Nemo"}, Cat{"Garfield"}, Dog{"Snoopy"});
auto names = hana::transform(animals, [](auto a) {
return a.name;
});
assert(hana::reverse(names) == hana::make_tuple("Snoopy", "Garfield", "Nemo"));
// No compile-time information is lost: even if `animals` can't be a
// constant expression because it contains strings, its length is constexpr.
static_assert(hana::length(animals) == 3u, "");
// Computations on types can be performed with the same syntax as that of
// normal C++. Believe it or not, everything is done at compile-time.
auto animal_types = hana::make_tuple(hana::type_c<Fish*>, hana::type_c<Cat&>, hana::type_c<Dog*>);
auto animal_ptrs = hana::filter(animal_types, [](auto a) {
return hana::traits::is_pointer(a);
});
static_assert(animal_ptrs == hana::make_tuple(hana::type_c<Fish*>, hana::type_c<Dog*>), "");
// And many other goodies to make your life easier, including:
// 1. Access to elements in a tuple with a sane syntax.
static_assert(animal_ptrs[0_c] == hana::type_c<Fish*>, "");
static_assert(animal_ptrs[1_c] == hana::type_c<Dog*>, "");
// 2. Unroll loops at compile-time without hassle.
std::string s;
hana::int_c<10>.times([&]{ s += "x"; });
// equivalent to s += "x"; s += "x"; ... s += "x";
// 3. Easily check whether an expression is valid.
// This is usually achieved with complex SFINAE-based tricks.
auto has_name = hana::is_valid([](auto&& x) -> decltype((void)x.name) { });
static_assert(has_name(animals[0_c]), "");
static_assert(!has_name(1), "");
}
Depends (5)
Builds
toolchain |
public-0.16.0 |
target |
x86_64-microsoft-win32-msvc14.3 |
tgt config |
windows_10-msvc_17.6-static_O2 |
timestamp |
2024-04-19 03:55:56 UTC (03:58:01 hours ago) |
result |
success | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-microsoft-win32-msvc14.3 |
tgt config |
windows_10-msvc_17.6-O2 |
timestamp |
2024-04-19 03:54:36 UTC (03:59:21 hours ago) |
result |
success | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-microsoft-win32-msvc14.3 |
tgt config |
windows_10-msvc_17.6 |
timestamp |
2024-04-19 03:53:22 UTC (04:00:35 hours ago) |
result |
success | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-w64-mingw32 |
tgt config |
windows_10-gcc_12.2_mingw_w64-static_O2 |
timestamp |
2024-04-19 03:16:35 UTC (04:37:22 hours ago) |
result |
success | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-w64-mingw32 |
tgt config |
windows_10-gcc_12.2_mingw_w64-O2 |
timestamp |
2024-04-19 03:15:43 UTC (04:38:15 hours ago) |
result |
success | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-w64-mingw32 |
tgt config |
windows_10-gcc_12.2_mingw_w64 |
timestamp |
2024-04-19 03:10:32 UTC (04:43:25 hours ago) |
result |
success | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-microsoft-win32-msvc14.3 |
tgt config |
windows_10-msvc_17.5 |
timestamp |
2024-04-19 02:54:10 UTC (04:59:47 hours ago) |
result |
success | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-freebsd12.4 |
tgt config |
freebsd_12-clang_13.0 |
timestamp |
2024-04-19 02:26:24 UTC (05:27:33 hours ago) |
result |
success | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_debian_11-gcc_12.1 |
timestamp |
2024-04-19 02:16:22 UTC (05:37:35 hours ago) |
result |
success | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_debian_12-clang_16.0-static_O3 |
timestamp |
2024-04-18 12:01:49 UTC (19:52:09 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_debian_12-clang_16.0_libc++-static_O3 |
timestamp |
2024-04-18 12:01:36 UTC (19:52:21 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_debian_12-clang_16.0_libc++-O3 |
timestamp |
2024-04-18 12:01:16 UTC (19:52:41 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_debian_12-clang_16.0_libc++ |
timestamp |
2024-04-18 12:01:09 UTC (19:52:48 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_debian_12-clang_16.0-O3 |
timestamp |
2024-04-18 12:00:57 UTC (19:53:00 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-microsoft-win32-msvc14.3 |
tgt config |
windows_10-clang_16.0_llvm_msvc_17.6-O2 |
timestamp |
2024-04-18 12:00:47 UTC (19:53:10 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_debian_12-clang_16.0 |
timestamp |
2024-04-18 12:00:16 UTC (19:53:41 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-microsoft-win32-msvc14.3 |
tgt config |
windows_10-clang_16.0_llvm_msvc_17.6-static_O2 |
timestamp |
2024-04-18 11:59:07 UTC (19:54:50 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-microsoft-win32-msvc14.3 |
tgt config |
windows_10-clang_16.0_llvm_msvc_17.6 |
timestamp |
2024-04-18 11:57:26 UTC (19:56:32 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_fedora_38-gcc_13-bindist |
timestamp |
2024-04-18 11:42:56 UTC (20:11:01 hours ago) |
result |
warning (update) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_debian_12-gcc_13.1-static_O3 |
timestamp |
2024-04-18 11:31:03 UTC (20:22:54 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
aarch64-linux-gnu |
tgt config |
linux_debian_12-clang_15_libc++ |
timestamp |
2024-04-18 11:30:54 UTC (20:23:04 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
aarch64-linux-gnu |
tgt config |
linux_debian_12-clang_15 |
timestamp |
2024-04-18 11:30:22 UTC (20:23:35 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_debian_12-gcc_13.1 |
timestamp |
2024-04-18 11:30:17 UTC (20:23:40 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_debian_12-gcc_13.1-ndebug_O3 |
timestamp |
2024-04-18 11:30:05 UTC (20:23:52 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_debian_12-gcc_13.1-O3 |
timestamp |
2024-04-18 11:29:52 UTC (20:24:05 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-microsoft-win32-msvc14.3 |
tgt config |
windows_10-clang_15.0_msvc_msvc_17.6 |
timestamp |
2024-04-18 11:20:52 UTC (20:33:06 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-freebsd13.2 |
tgt config |
freebsd_13-clang_14.0-O3 |
timestamp |
2024-04-18 11:05:34 UTC (20:48:23 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_debian_12-clang_15.0 |
timestamp |
2024-04-18 11:05:05 UTC (20:48:53 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-freebsd13.2 |
tgt config |
freebsd_13-clang_14.0-static_O3 |
timestamp |
2024-04-18 11:04:49 UTC (20:49:08 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_debian_12-clang_15.0_libc++ |
timestamp |
2024-04-18 11:04:30 UTC (20:49:27 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-freebsd13.2 |
tgt config |
freebsd_13-clang_14.0 |
timestamp |
2024-04-18 11:03:09 UTC (20:50:49 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-apple-darwin22.5.0 |
tgt config |
macos_13-clang_14.0-static_O3 |
timestamp |
2024-04-17 12:59:53 UTC (01 18:54:04 days ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-apple-darwin22.5.0 |
tgt config |
macos_13-clang_14.0-O3 |
timestamp |
2024-04-17 12:59:15 UTC (01 18:54:42 days ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-apple-darwin22.5.0 |
tgt config |
macos_13-clang_14.0 |
timestamp |
2024-04-17 12:58:33 UTC (01 18:55:25 days ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-apple-darwin22.5.0 |
tgt config |
macos_13-clang_15.0-static_O3 |
timestamp |
2024-04-16 21:58:42 UTC (02 09:55:15 days ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-apple-darwin22.5.0 |
tgt config |
macos_13-clang_15.0-O3 |
timestamp |
2024-04-16 21:53:43 UTC (02 10:00:14 days ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-apple-darwin22.5.0 |
tgt config |
macos_13-clang_15.0 |
timestamp |
2024-04-16 21:53:03 UTC (02 10:00:54 days ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_fedora_37-gcc_12.2-bindist |
timestamp |
2024-04-16 20:05:16 UTC (02 11:48:41 days ago) |
result |
success | log | rebuild |
toolchain |
public-0.16.0 |
target |
aarch64-linux-gnu |
tgt config |
linux_debian_12-clang_16_libc++-static_O3 |
timestamp |
2024-04-16 15:05:11 UTC (02 16:48:46 days ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
aarch64-linux-gnu |
tgt config |
linux_debian_12-clang_16_libc++-O3 |
timestamp |
2024-04-16 15:04:36 UTC (02 16:49:21 days ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
aarch64-linux-gnu |
tgt config |
linux_debian_12-clang_16-static_O3 |
timestamp |
2024-04-16 15:03:42 UTC (02 16:50:15 days ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
aarch64-linux-gnu |
tgt config |
linux_debian_12-clang_16_libc++ |
timestamp |
2024-04-16 15:03:30 UTC (02 16:50:28 days ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
aarch64-linux-gnu |
tgt config |
linux_debian_12-clang_16-O3 |
timestamp |
2024-04-16 15:03:08 UTC (02 16:50:50 days ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
aarch64-linux-gnu |
tgt config |
linux_debian_12-clang_16 |
timestamp |
2024-04-16 15:02:28 UTC (02 16:51:30 days ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
aarch64-linux-gnu |
tgt config |
linux_debian_12-gcc_13-static_O3 |
timestamp |
2024-04-16 11:05:11 UTC (02 20:48:46 days ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
aarch64-linux-gnu |
tgt config |
linux_debian_12-gcc_13-O3 |
timestamp |
2024-04-16 11:04:06 UTC (02 20:49:51 days ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
aarch64-linux-gnu |
tgt config |
linux_debian_12-gcc_13-ndebug_O3 |
timestamp |
2024-04-16 11:00:14 UTC (02 20:53:43 days ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
aarch64-linux-gnu |
tgt config |
linux_debian_12-gcc_13 |
timestamp |
2024-04-16 10:59:40 UTC (02 20:54:17 days ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
toolchain |
public-0.16.0 |
target |
aarch64-linux-gnu |
tgt config |
linux_debian_11-gcc_12 |
timestamp |
2024-04-16 09:13:34 UTC (02 22:40:24 days ago) |
result |
success | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_debian_12-gcc_12-bindist |
timestamp |
2024-04-16 08:23:59 UTC (02 23:29:58 days ago) |
result |
success | log | rebuild |
target |
x86_64-apple-darwin22.5.0 |
tgt config |
macos_13-gcc_13_homebrew |
result |
excluded (https://github) |
target |
x86_64-apple-darwin22.5.0 |
tgt config |
macos_13-gcc_13_homebrew-O3 |
result |
excluded (https://github) |
target |
x86_64-apple-darwin22.5.0 |
tgt config |
macos_13-gcc_13_homebrew-static_O3 |
result |
excluded (https://github) |