Added category::find1<std::optional>

changelog

@@ -3,6 +3,7 @@ Version 5.0.9
 - Added create_water to model
 - Added create_water to model
 - Writing twin domain info in PDB files and more PDB fixes
 - Writing twin domain info in PDB files and more PDB fixes
 - remove_atom improved (remove struct_conn records)
 - remove_atom improved (remove struct_conn records)
+- Added a specialisation for category::find1<std::optional>
 
 
 Version 5.0.8
 Version 5.0.8
 - implemented find_first, find_min, find_max and count in category
 - implemented find_first, find_min, find_max and count in category

include/cif++/category.hpp

@@ -64,6 +64,12 @@ class multiple_results_error : public std::runtime_error
 };
 };
 
 
 // --------------------------------------------------------------------
 // --------------------------------------------------------------------
+// These should be moved elsewhere, one day.
+
+template<typename _Tp> inline constexpr bool is_optional_v = false;
+template<typename _Tp> inline constexpr bool is_optional_v<std::optional<_Tp>> = true;
+
+// --------------------------------------------------------------------
 
 
 class category
 class category
 {
 {
@@ -299,7 +305,7 @@ class category
 		return find1<T>(cbegin(), std::move(cond), column);
 		return find1<T>(cbegin(), std::move(cond), column);
 	}
 	}
 
 
-	template <typename T>
+	template <typename T, std::enable_if_t<not is_optional_v<T>, int> = 0>
 	T find1(const_iterator pos, condition &&cond, const char *column) const
 	T find1(const_iterator pos, condition &&cond, const char *column) const
 	{
 	{
 		auto h = find<T>(pos, std::move(cond), column);
 		auto h = find<T>(pos, std::move(cond), column);
@@ -310,6 +316,20 @@ class category
 		return *h.begin();
 		return *h.begin();
 	}
 	}
 
 
+	template <typename T, std::enable_if_t<is_optional_v<T>, int> = 0>
+	T find1(const_iterator pos, condition &&cond, const char *column) const
+	{
+		auto h = find<typename T::value_type>(pos, std::move(cond), column);
+
+		if (h.size() > 1)
+			throw multiple_results_error();
+
+		if (h.empty())
+			return {};
+
+		return *h.begin();
+	}
+
 	template <typename... Ts, typename... Cs, typename U = std::enable_if_t<sizeof...(Ts) != 1>>
 	template <typename... Ts, typename... Cs, typename U = std::enable_if_t<sizeof...(Ts) != 1>>
 	std::tuple<Ts...> find1(condition &&cond, Cs... columns) const
 	std::tuple<Ts...> find1(condition &&cond, Cs... columns) const
 	{
 	{

src/point.cpp

@@ -299,17 +299,6 @@ quaternion_type<T> normalize(quaternion_type<T> q)
 
 
 quaternion construct_from_angle_axis(float angle, point axis)
 quaternion construct_from_angle_axis(float angle, point axis)
 {
 {
-	// auto q = std::cos((angle * kPI / 180) / 2);
-	// auto s = std::sqrt(1 - q * q);
-
-	// axis.normalize();
-
-	// return normalize(quaternion{
-	// 	static_cast<float>(q),
-	// 	static_cast<float>(s * axis.m_x),
-	// 	static_cast<float>(s * axis.m_y),
-	// 	static_cast<float>(s * axis.m_z) });
-
 	angle = (angle * kPI / 180) / 2;
 	angle = (angle * kPI / 180) / 2;
 	auto s = std::sin(angle);
 	auto s = std::sin(angle);
 	auto c = std::cos(angle);
 	auto c = std::cos(angle);

test/unit-v2-test.cpp

@@ -3104,3 +3104,30 @@ _date    today
 
 
 	BOOST_TEST(db == db2);
 	BOOST_TEST(db == db2);
 }
 }
+
+BOOST_AUTO_TEST_CASE(find1_opt_1)
+{
+	using namespace cif::literals;
+	using namespace std::literals;
+
+	auto f = R"(data_TEST
+#
+loop_
+_test.id
+_test.name
+_test.value
+1 aap   1.0
+2 noot  1.1
+3 mies  1.2
+    )"_cf;
+
+	auto &db = f.front();
+	auto &test = db["test"];
+
+	auto v = test.find1<std::optional<float>>("id"_key == 1, "value");
+	BOOST_CHECK(v.has_value());
+	BOOST_TEST(*v == 1.0f);
+
+	v = test.find1<std::optional<float>>("id"_key == 4, "value");
+	BOOST_CHECK(v.has_value() == false);
+}
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