Add operator< to , to allow use as a map key

nlohmann · Aug 5, 2022 · 9ebfeb7 · 9ebfeb7
1 parent 7b6cf59
commit 9ebfeb7
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Showing 2 changed files with 44 additions and 0 deletions.
diff --git a/include/nlohmann/detail/json_pointer.hpp b/include/nlohmann/detail/json_pointer.hpp
@@ -862,6 +862,15 @@ class json_pointer
     {
         return *this == json_pointer(rhs);
     }
+
+    /// @brief compares JSON pointer and string for less-than
+    template<typename RefStringTypeLhs, typename RefStringTypeRhs>
+    friend bool operator<(json_pointer<RefStringTypeLhs> const& lhs,
+                          json_pointer<RefStringTypeRhs> const& rhs) noexcept
+    {
+        return lhs.reference_tokens < rhs.reference_tokens;
+    }
+
 #else
     /// @brief compares two JSON pointers for equality
     /// @sa https://json.nlohmann.me/api/json_pointer/operator_eq/
@@ -904,6 +913,12 @@ class json_pointer
     // NOLINTNEXTLINE(readability-redundant-declaration)
     friend bool operator!=(const StringType& lhs,
                            const json_pointer<RefStringTypeRhs>& rhs);
+
+    /// @brief compares string and JSON pointer for less-than
+    template<typename RefStringTypeRhs, typename StringType>
+    // NOLINTNEXTLINE(readability-redundant-declaration)
+    friend bool operator<(const StringType& lhs,
+                          const json_pointer<RefStringTypeRhs>& rhs);
 #endif
 
   private:
@@ -958,6 +973,13 @@ inline bool operator!=(const StringType& lhs,
 {
     return !(lhs == rhs);
 }
+
+template<typename RefStringTypeLhs, typename RefStringTypeRhs>
+inline bool operator<(const json_pointer<RefStringTypeLhs>& lhs,
+                      const json_pointer<RefStringTypeRhs>& rhs) noexcept
+{
+    return lhs.reference_tokens < rhs.reference_tokens;
+}
 #endif
 
 NLOHMANN_JSON_NAMESPACE_END
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
@@ -14464,6 +14464,15 @@ class json_pointer
     {
         return *this == json_pointer(rhs);
     }
+
+    /// @brief compares JSON pointer and string for less-than
+    template<typename RefStringTypeLhs, typename RefStringTypeRhs>
+    friend bool operator<(json_pointer<RefStringTypeLhs> const& lhs,
+                          json_pointer<RefStringTypeRhs> const& rhs) noexcept
+    {
+        return lhs.reference_tokens < rhs.reference_tokens;
+    }
+
 #else
     /// @brief compares two JSON pointers for equality
     /// @sa https://json.nlohmann.me/api/json_pointer/operator_eq/
@@ -14506,6 +14515,12 @@ class json_pointer
     // NOLINTNEXTLINE(readability-redundant-declaration)
     friend bool operator!=(const StringType& lhs,
                            const json_pointer<RefStringTypeRhs>& rhs);
+
+    /// @brief compares string and JSON pointer for less-than
+    template<typename RefStringTypeRhs, typename StringType>
+    // NOLINTNEXTLINE(readability-redundant-declaration)
+    friend bool operator<(const StringType& lhs,
+                          const json_pointer<RefStringTypeRhs>& rhs);
 #endif
 
   private:
@@ -14560,6 +14575,13 @@ inline bool operator!=(const StringType& lhs,
 {
     return !(lhs == rhs);
 }
+
+template<typename RefStringTypeLhs, typename RefStringTypeRhs>
+inline bool operator<(const json_pointer<RefStringTypeLhs>& lhs,
+                      const json_pointer<RefStringTypeRhs>& rhs) noexcept
+{
+    return lhs.reference_tokens < rhs.reference_tokens;
+}
 #endif
 
 NLOHMANN_JSON_NAMESPACE_END