replace nihil::generator

the new implementation is much simpler and PD-licensed.  the only
downside is it doesn't support elements_of.

while here, move it to nihil.core.

1 files changed, 109 insertions, 0 deletions

diff --git a/nihil.core/generator.test.cc b/nihil.core/generator.test.cc
new file mode 100644
index 0000000..1fc0f22
--- /dev/null
+++ b/nihil.core/generator.test.cc
@@ -0,0 +1,109 @@
+// This source code is released into the public domain.
+
+#include <catch2/catch_test_macros.hpp>
+
+import nihil.std;
+import nihil.core;
+
+namespace {
+inline auto constexpr test_tags = "[nihil][nihil.generator]";
+
+SCENARIO("A generator that yields values", test_tags)
+{
+	GIVEN ("A generator that yields values") {
+		auto fn = [&]() -> nihil::generator<int> {
+			co_yield 1;
+			co_yield 2;
+		};
+
+		THEN ("The generator yields the original values") {
+			REQUIRE(std::ranges::equal(fn(), std::vector{1, 2}));
+		}
+	}
+}
+
+SCENARIO("A generator that yields references", test_tags)
+{
+	GIVEN ("A generator that yields references") {
+		auto one = 1, two = 2;
+		auto fn = [&]() -> nihil::generator<int &> {
+			co_yield one;
+			co_yield two;
+		};
+		auto range = fn();
+
+		THEN ("The references refer to the original values") {
+			auto it = std::ranges::begin(range);
+			REQUIRE(&*it == &one);
+			++it;
+			REQUIRE(&*it == &two);
+			++it;
+			REQUIRE(it == std::ranges::end(range));
+		}
+	}
+}
+
+SCENARIO("A generator that yields pointers", test_tags)
+{
+	GIVEN ("A generator that yields pointers") {
+		auto one = 1, two = 2;
+		auto fn = [&]() -> nihil::generator<int *> {
+			co_yield &one;
+			co_yield &two;
+		};
+
+		THEN ("The pointers point to the original values") {
+			REQUIRE(std::ranges::equal(fn(), std::vector{&one, &two}));
+		}
+	}
+}
+
+SCENARIO("A generator that yields lvalues", test_tags)
+{
+	GIVEN ("A generator that yields pointers") {
+		auto one = 1, two = 2;
+		auto fn = [&]() -> nihil::generator<int> {
+			co_yield one;
+			co_yield two;
+		};
+
+		THEN ("The pointers point to the original values") {
+			REQUIRE(std::ranges::equal(fn(), std::vector{1, 2}));
+		}
+	}
+}
+
+TEST_CASE("generator: exceptions", "[generator]")
+{
+	auto fn = []() -> nihil::generator<int> {
+		co_yield 1;
+		throw std::runtime_error("test");
+	};
+
+	auto range = fn();
+	auto it = std::ranges::begin(range);
+	REQUIRE(*it == 1);
+	REQUIRE_THROWS_AS(it++, std::runtime_error);
+}
+
+#if 0
+// TODO: Re-enable this test once we have a standard-compliant generator.
+TEST_CASE("generator: elements_of", "[generator]")
+{
+	auto fn1 = [] -> nihil::generator<int> {
+		co_yield 1;
+		co_yield 2;
+		co_yield 3;
+	};
+
+	auto fn2 = [&fn1] -> nihil::generator<int> {
+		co_yield nihil::elements_of(fn1());
+	};
+
+	auto values = std::vector<int>();
+	std::ranges::copy(fn2(), std::back_inserter(values));
+
+	REQUIRE(values == std::vector{1, 2, 3});
+}
+#endif
+} // anonymous namespace