Support conversion for std::valarray (#956)

include/yaml-cpp/node/convert.h

@@ -15,6 +15,7 @@
 #include <unordered_map>
 #include <sstream>
 #include <type_traits>
+#include <valarray>
 #include <vector>
 
 #include "yaml-cpp/binary.h"
@@ -363,6 +364,37 @@ struct convert<std::array<T, N>> {
   }
 };
 
+
+// std::valarray
+template <typename T>
+struct convert<std::valarray<T>> {
+  static Node encode(const std::valarray<T>& rhs) {
+    Node node(NodeType::Sequence);
+    for (const auto& element : rhs) {
+      node.push_back(element);
+    }
+    return node;
+  }
+
+  static bool decode(const Node& node, std::valarray<T>& rhs) {
+    if (!node.IsSequence()) {
+      return false;
+    }
+
+    rhs.resize(node.size());
+    for (auto i = 0u; i < node.size(); ++i) {
+#if defined(__GNUC__) && __GNUC__ < 4
+      // workaround for GCC 3:
+      rhs[i] = node[i].template as<T>();
+#else
+      rhs[i] = node[i].as<T>();
+#endif
+    }
+    return true;
+  }
+};
+
+
 // std::pair
 template <typename T, typename U>
 struct convert<std::pair<T, U>> {

test/node/node_test.cpp

@@ -352,6 +352,16 @@ TEST(NodeTest, StdArrayWrongSize) {
       (node["evens"].as<std::array<int, 5>>()), ErrorMsg::BAD_CONVERSION);
 }
 
+TEST(NodeTest, StdValrray) {
+  std::valarray<int> evens{{2, 4, 6, 8, 10}};
+  Node node;
+  node["evens"] = evens;
+  std::valarray<int> actualEvens = node["evens"].as<std::valarray<int>>();
+  for (int i = 0; i < evens.size(); ++i) {
+    EXPECT_EQ(evens[i], actualEvens[i]);
+  }
+}
+
 TEST(NodeTest, StdVector) {
   std::vector<int> primes;
   primes.push_back(2);