diff --git a/json11.cpp b/json11.cpp
index d60c84f..e0ae291 100644
--- a/json11.cpp
+++ b/json11.cpp
@@ -169,6 +169,7 @@ protected:
 };
 
 class JsonDouble final : public Value<Json::NUMBER, double> {
+    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); }
     uint64_ uint64_value() const override { return static_cast<uint64_>(m_value); }
@@ -179,6 +180,7 @@ public:
 };
 
 class JsonInt64 final : public Value<Json::NUMBER, int64_> {
+    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); }
     uint64_ uint64_value() const override { return static_cast<uint64_>(m_value); }
@@ -189,6 +191,7 @@ public:
 };
 
 class JsonUInt64 final : public Value<Json::NUMBER, uint64_> {
+    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); }
     uint64_ uint64_value() const override { return static_cast<uint64_>(m_value); }
@@ -206,6 +209,7 @@ public:
 
 class JsonString final : public Value<Json::STRING, string> {
     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 { size_t pos = 0; double v = std::stod(m_value, &pos); if (pos < m_value.length()) { v = 0; } return v; }
     int64_ int64_value() const override { size_t pos = 0; int64_ v = std::stoll(m_value, &pos); if (pos < m_value.length()) { v = 0; } return v; }
     uint64_ uint64_value() const override { size_t pos = 0; uint64_ v = std::stoull(m_value, &pos); if (pos < m_value.length()) { v = 0; } return v; }