Fix compilation under clang

json11.cpp

@@ -41,10 +41,6 @@ using std::move;
  * Serialization
  */
 
-static void dump(std::nullptr_t, string &out) {
-    out += "null";
-}
-
 static void dump(double value, string &out) {
     if (std::isfinite(value)) {
         char buf[32];
@@ -55,10 +51,6 @@ static void dump(double value, string &out) {
     }
 }
 
-static void dump(int value, string &out) {
-    out += std::to_string(value);
-}
-
 static void dump(int64_ value, string &out) {
     out += std::to_string(value);
 }
@@ -169,7 +161,7 @@ protected:
 };
 
 class JsonDouble final : public Value<Json::NUMBER, double> {
-    string as_string() const { return std::to_string(m_value); }
+    string as_string() const override { return std::to_string(m_value); }
     bool bool_value() const override { return m_value != 0; }
     double number_value() const override { return static_cast<double>(m_value); }
     int64_ int64_value() const override { return static_cast<int64_>(m_value); }
@@ -181,7 +173,7 @@ public:
 };
 
 class JsonInt64 final : public Value<Json::NUMBER, int64_> {
-    string as_string() const { return std::to_string(m_value); }
+    string as_string() const override { return std::to_string(m_value); }
     bool bool_value() const override { return m_value != 0; }
     double number_value() const override { return static_cast<double>(m_value); }
     int64_ int64_value() const override { return static_cast<int64_>(m_value); }
@@ -193,7 +185,7 @@ public:
 };
 
 class JsonUInt64 final : public Value<Json::NUMBER, uint64_> {
-    string as_string() const { return std::to_string(m_value); }
+    string as_string() const override { return std::to_string(m_value); }
     bool bool_value() const override { return m_value != 0; }
     double number_value() const override { return static_cast<double>(m_value); }
     int64_ int64_value() const override { return static_cast<int64_>(m_value); }
@@ -211,7 +203,7 @@ public:
 };
 
 class JsonString final : public Value<Json::STRING, string> {
-    string as_string() const { return m_value; }
+    string as_string() const override { return m_value; }
     const string &string_value() const override { return m_value; }
     bool bool_value() const override { return m_value != "" && m_value != "0"; }
     double number_value() const override
@@ -259,9 +251,23 @@ public:
     explicit JsonObject(Json::object &&value)      : Value(move(value)) {}
 };
 
-class JsonNull final : public Value<Json::NUL, std::nullptr_t> {
+class JsonNull final : public JsonValue {
 public:
-    JsonNull() : Value(nullptr) {}
+    JsonNull() {}
+    // Get type tag
+    Json::Type type() const override {
+        return Json::NUL;
+    }
+    // Comparisons - only within type
+    bool equals(const JsonValue * other) const override {
+        return true;
+    }
+    bool less(const JsonValue * other) const override {
+        return false;
+    }
+    void dump(string &out) const override {
+        out += "null";
+    }
 };
 
 /* * * * * * * * * * * * * * * * * * * *