Make sure that floating point values are serialized properly in YAML; #363 (#370)

Author: liuzicheng1987

include/rfl/yaml/Writer.hpp

@@ -88,10 +88,14 @@ class Writer {
                              const T& _var) const noexcept {
     if constexpr (std::is_same<std::remove_cvref_t<T>, std::string>() ||
                   std::is_same<std::remove_cvref_t<T>, bool>() ||
-                  std::is_floating_point<std::remove_cvref_t<T>>() ||
                   std::is_same<std::remove_cvref_t<T>,
                                std::remove_cvref_t<decltype(YAML::Null)>>()) {
       (*out_) << YAML::Key << _name.data() << YAML::Value << _var;
+    } else if constexpr (std::is_floating_point<std::remove_cvref_t<T>>()) {
+      // std::to_string is necessary to ensure that floating point values are
+      // always written as floats.
+      (*out_) << YAML::Key << _name.data() << YAML::Value
+              << std::to_string(_var);
     } else if constexpr (std::is_integral<std::remove_cvref_t<T>>()) {
       (*out_) << YAML::Key << _name.data() << YAML::Value
               << static_cast<int64_t>(_var);
@@ -103,7 +107,20 @@ class Writer {
 
   template <class T>
   OutputVarType insert_value(const T& _var) const noexcept {
-    (*out_) << _var;
+    if constexpr (std::is_same<std::remove_cvref_t<T>, std::string>() ||
+                  std::is_same<std::remove_cvref_t<T>, bool>() ||
+                  std::is_same<std::remove_cvref_t<T>,
+                               std::remove_cvref_t<decltype(YAML::Null)>>()) {
+      (*out_) << _var;
+    } else if constexpr (std::is_floating_point<std::remove_cvref_t<T>>()) {
+      // std::to_string is necessary to ensure that floating point values are
+      // always written as floats.
+      (*out_) << std::to_string(_var);
+    } else if constexpr (std::is_integral<std::remove_cvref_t<T>>()) {
+      (*out_) << static_cast<int64_t>(_var);
+    } else {
+      static_assert(rfl::always_false_v<T>, "Unsupported type.");
+    }
     return OutputVarType{};
   }
 

tests/yaml/test_double.cpp

@@ -0,0 +1,21 @@
+#include <iostream>
+#include <rfl.hpp>
+#include <string>
+#include <vector>
+
+#include "write_and_read.hpp"
+
+namespace test_double {
+
+TEST(yaml, test_double) {
+  auto obj = rfl::Generic::Object();
+  const double age = 10;
+  obj["age"] = age;
+  const auto s = rfl::yaml::write(obj);
+  EXPECT_EQ(
+      rfl::from_generic<double>(
+          rfl::yaml::read<rfl::Generic::Object>(s).value().get("age").value())
+          .value(),
+      10.0);
+}
+}  // namespace test_double