summaryrefslogtreecommitdiffstats
path: root/src/boost/libs/hana/example/integral_constant.cpp
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--src/boost/libs/hana/example/integral_constant.cpp101
1 files changed, 101 insertions, 0 deletions
diff --git a/src/boost/libs/hana/example/integral_constant.cpp b/src/boost/libs/hana/example/integral_constant.cpp
new file mode 100644
index 000000000..aaad126da
--- /dev/null
+++ b/src/boost/libs/hana/example/integral_constant.cpp
@@ -0,0 +1,101 @@
+// Copyright Louis Dionne 2013-2017
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+
+#include <boost/hana/assert.hpp>
+#include <boost/hana/config.hpp>
+#include <boost/hana/equal.hpp>
+#include <boost/hana/for_each.hpp>
+#include <boost/hana/integral_constant.hpp>
+#include <boost/hana/mult.hpp>
+#include <boost/hana/negate.hpp>
+#include <boost/hana/plus.hpp>
+#include <boost/hana/tuple.hpp>
+
+#include <string>
+#include <vector>
+namespace hana = boost::hana;
+
+
+int main() {
+
+{
+
+//! [operators]
+BOOST_HANA_CONSTANT_CHECK(hana::int_c<1> + hana::int_c<3> == hana::int_c<4>);
+
+// Mixed-type operations are supported, but only when it involves a
+// promotion, and not a conversion that could be lossy.
+BOOST_HANA_CONSTANT_CHECK(hana::size_c<3> * hana::ushort_c<5> == hana::size_c<15>);
+BOOST_HANA_CONSTANT_CHECK(hana::llong_c<15> == hana::int_c<15>);
+//! [operators]
+
+}{
+
+//! [times_loop_unrolling]
+std::string s;
+for (char c = 'x'; c <= 'z'; ++c)
+ hana::int_<5>::times([&] { s += c; });
+
+BOOST_HANA_RUNTIME_CHECK(s == "xxxxxyyyyyzzzzz");
+//! [times_loop_unrolling]
+
+}{
+
+//! [times_higher_order]
+std::string s;
+auto functions = hana::make_tuple(
+ [&] { s += "x"; },
+ [&] { s += "y"; },
+ [&] { s += "z"; }
+);
+hana::for_each(functions, hana::int_<5>::times);
+BOOST_HANA_RUNTIME_CHECK(s == "xxxxxyyyyyzzzzz");
+//! [times_higher_order]
+
+}{
+
+//! [from_object]
+std::string s;
+for (char c = 'x'; c <= 'z'; ++c)
+ hana::int_c<5>.times([&] { s += c; });
+
+BOOST_HANA_RUNTIME_CHECK(s == "xxxxxyyyyyzzzzz");
+//! [from_object]
+
+}{
+
+//! [times_with_index_runtime]
+std::vector<int> v;
+hana::int_<5>::times.with_index([&](auto index) { v.push_back(index); });
+
+BOOST_HANA_RUNTIME_CHECK(v == std::vector<int>{0, 1, 2, 3, 4});
+//! [times_with_index_runtime]
+
+//! [times_with_index_compile_time]
+constexpr auto xs = hana::tuple_c<int, 0, 1, 2>;
+hana::int_<3>::times.with_index([xs](auto index) {
+ BOOST_HANA_CONSTANT_CHECK(xs[index] == index);
+});
+//! [times_with_index_compile_time]
+
+}{
+
+//! [literals]
+using namespace hana::literals; // contains the _c suffix
+
+BOOST_HANA_CONSTANT_CHECK(1234_c == hana::llong_c<1234>);
+BOOST_HANA_CONSTANT_CHECK(-1234_c == hana::llong_c<-1234>);
+BOOST_HANA_CONSTANT_CHECK(1_c + (3_c * 4_c) == hana::llong_c<1 + (3 * 4)>);
+//! [literals]
+
+}{
+
+//! [integral_c]
+BOOST_HANA_CONSTANT_CHECK(hana::integral_c<int, 2> == hana::int_c<2>);
+static_assert(decltype(hana::integral_c<int, 2>)::value == 2, "");
+//! [integral_c]
+
+}
+
+}