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-apple-darwin22.5.0 |
tgt config |
macos_13-clang_15.0-static_O3 |
timestamp |
2024-04-27 21:56:42 UTC (05:50:53 hours ago) |
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warning (update) | warning (test-installed) | log | rebuild |
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public-0.16.0 |
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x86_64-apple-darwin22.5.0 |
tgt config |
macos_13-clang_15.0-O3 |
timestamp |
2024-04-27 21:54:23 UTC (05:53:12 hours ago) |
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warning (update) | warning (test-installed) | log | rebuild |
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public-0.16.0 |
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x86_64-apple-darwin22.5.0 |
tgt config |
macos_13-clang_15.0 |
timestamp |
2024-04-27 21:51:26 UTC (05:56:09 hours ago) |
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public-0.16.0 |
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x86_64-linux-gnu |
tgt config |
linux_fedora_37-gcc_12.2-bindist |
timestamp |
2024-04-27 20:10:04 UTC (07:37:31 hours ago) |
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success | log | rebuild |
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public-0.16.0 |
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aarch64-linux-gnu |
tgt config |
linux_debian_12-clang_16_libc++-static_O3 |
timestamp |
2024-04-27 13:37:20 UTC (14:10:15 hours ago) |
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warning (update) | warning (test-installed) | log | rebuild |
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public-0.16.0 |
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aarch64-linux-gnu |
tgt config |
linux_debian_12-clang_16_libc++-O3 |
timestamp |
2024-04-27 13:36:47 UTC (14:10:49 hours ago) |
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public-0.16.0 |
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aarch64-linux-gnu |
tgt config |
linux_debian_12-clang_16_libc++ |
timestamp |
2024-04-27 13:36:21 UTC (14:11:14 hours ago) |
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warning (update) | warning (test-installed) | log | rebuild |
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public-0.16.0 |
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aarch64-linux-gnu |
tgt config |
linux_debian_12-clang_16-static_O3 |
timestamp |
2024-04-27 13:36:13 UTC (14:11:23 hours ago) |
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public-0.16.0 |
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aarch64-linux-gnu |
tgt config |
linux_debian_12-clang_16 |
timestamp |
2024-04-27 13:35:49 UTC (14:11:46 hours ago) |
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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 |
2024-04-27 13:35:39 UTC (14:11:56 hours ago) |
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warning (update) | warning (test-installed) | log | rebuild |
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public-0.16.0 |
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aarch64-linux-gnu |
tgt config |
linux_debian_12-gcc_13-ndebug_O3 |
timestamp |
2024-04-27 11:12:30 UTC (16:35:05 hours ago) |
result |
warning (update) | warning (test-installed) | log | rebuild |
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public-0.16.0 |
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aarch64-linux-gnu |
tgt config |
linux_debian_12-gcc_13-static_O3 |
timestamp |
2024-04-27 11:10:51 UTC (16:36:44 hours ago) |
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toolchain |
public-0.16.0 |
target |
aarch64-linux-gnu |
tgt config |
linux_debian_12-gcc_13 |
timestamp |
2024-04-27 11:10:39 UTC (16:36:56 hours ago) |
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public-0.16.0 |
target |
aarch64-linux-gnu |
tgt config |
linux_debian_12-gcc_13-O3 |
timestamp |
2024-04-27 11:10:19 UTC (16:37:16 hours ago) |
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public-0.16.0 |
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aarch64-linux-gnu |
tgt config |
linux_debian_11-gcc_12 |
timestamp |
2024-04-27 09:13:16 UTC (18:34:19 hours ago) |
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success | log | rebuild |
toolchain |
public-0.16.0 |
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x86_64-linux-gnu |
tgt config |
linux_debian_12-gcc_12-bindist |
timestamp |
2024-04-27 08:24:34 UTC (19:23:01 hours ago) |
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success | log | rebuild |
toolchain |
public-0.16.0 |
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x86_64-microsoft-win32-msvc14.3 |
tgt config |
windows_10-msvc_17.6-static_O2 |
timestamp |
2024-04-27 03:55:22 UTC (23:52:13 hours ago) |
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success | log | rebuild |
toolchain |
public-0.16.0 |
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x86_64-microsoft-win32-msvc14.3 |
tgt config |
windows_10-msvc_17.6-O2 |
timestamp |
2024-04-27 03:52:50 UTC (23:54:45 hours ago) |
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toolchain |
public-0.16.0 |
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x86_64-microsoft-win32-msvc14.3 |
tgt config |
windows_10-msvc_17.6 |
timestamp |
2024-04-27 03:51:10 UTC (23:56:25 hours ago) |
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toolchain |
public-0.16.0 |
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x86_64-w64-mingw32 |
tgt config |
windows_10-gcc_12.2_mingw_w64-static_O2 |
timestamp |
2024-04-27 03:14:43 UTC (01 00:32:52 days ago) |
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toolchain |
public-0.16.0 |
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x86_64-w64-mingw32 |
tgt config |
windows_10-gcc_12.2_mingw_w64 |
timestamp |
2024-04-27 03:11:25 UTC (01 00:36:10 days ago) |
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success | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-w64-mingw32 |
tgt config |
windows_10-gcc_12.2_mingw_w64-O2 |
timestamp |
2024-04-27 03:10:05 UTC (01 00:37:31 days ago) |
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success | log | rebuild |
toolchain |
public-0.16.0 |
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x86_64-microsoft-win32-msvc14.3 |
tgt config |
windows_10-msvc_17.5 |
timestamp |
2024-04-27 02:55:23 UTC (01 00:52:12 days ago) |
result |
success | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-freebsd12.4 |
tgt config |
freebsd_12-clang_13.0 |
timestamp |
2024-04-27 02:21:57 UTC (01 01:25:39 days ago) |
result |
success | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_debian_11-gcc_12.1 |
timestamp |
2024-04-27 02:14:47 UTC (01 01:32:48 days ago) |
result |
success | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_debian_12-clang_16.0_libc++-O3 |
timestamp |
2024-04-26 12:35:32 UTC (01 15:12:04 days 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 |
2024-04-26 12:35:30 UTC (01 15:12:05 days 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 |
2024-04-26 12:35:25 UTC (01 15:12:11 days 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-static_O3 |
timestamp |
2024-04-26 12:35:00 UTC (01 15:12:35 days 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 |
2024-04-26 12:34:52 UTC (01 15:12:43 days 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 |
2024-04-26 12:34:34 UTC (01 15:13:02 days 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 |
2024-04-26 12:32:21 UTC (01 15:15:14 days 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 |
2024-04-26 12:29:51 UTC (01 15:17:45 days 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 |
2024-04-26 12:29:49 UTC (01 15:17:46 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_15_libc++ |
timestamp |
2024-04-26 12:22:49 UTC (01 15:24:46 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_15 |
timestamp |
2024-04-26 12:21:08 UTC (01 15:26:27 days 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 |
2024-04-26 12:16:26 UTC (01 15:31:09 days ago) |
result |
warning (update) | log | rebuild |
toolchain |
public-0.16.0 |
target |
x86_64-linux-gnu |
tgt config |
linux_debian_12-gcc_13.1 |
timestamp |
2024-04-26 12:02:06 UTC (01 15:45:30 days 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 |
2024-04-26 12:01:33 UTC (01 15:46:02 days 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 |
2024-04-26 12:01:22 UTC (01 15:46:14 days 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-static_O3 |
timestamp |
2024-04-26 12:00:49 UTC (01 15:46:46 days 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 |
2024-04-26 11:48:10 UTC (01 15:59:26 days 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 |
2024-04-26 11:44:00 UTC (01 16:03:35 days 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 |
2024-04-26 11:39:02 UTC (01 16:08:33 days 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 |
2024-04-26 11:38:53 UTC (01 16:08:43 days 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 |
2024-04-26 11:38:44 UTC (01 16:08:51 days 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 |
2024-04-26 11:37:49 UTC (01 16:09:46 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-static_O3 |
timestamp |
2024-04-25 13:52:28 UTC (02 13:55:07 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 |
2024-04-25 13:49:56 UTC (02 13:57:39 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 |
2024-04-25 13:47:27 UTC (02 14:00:08 days ago) |
result |
warning (update) | warning (test-installed) | 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) |