From 0f6d47133e5497fc42a9ef8a18291b1835a17eef Mon Sep 17 00:00:00 2001
From: barcode <barcode@example.com>
Date: Mon, 26 Dec 2022 17:46:00 +0100
Subject: [PATCH] Add nlohmann::json::as_base_class

---
 docs/examples/as_base_class.cpp               | 40 +++++++++++++++++++
 docs/examples/as_base_class.output            |  3 ++
 .../docs/api/basic_json/as_base_class.md      | 32 +++++++++++++++
 docs/mkdocs/docs/api/basic_json/index.md      |  1 +
 docs/mkdocs/mkdocs.yml                        |  1 +
 include/nlohmann/json.hpp                     | 10 +++++
 single_include/nlohmann/json.hpp              | 10 +++++
 7 files changed, 97 insertions(+)
 create mode 100644 docs/examples/as_base_class.cpp
 create mode 100644 docs/examples/as_base_class.output
 create mode 100644 docs/mkdocs/docs/api/basic_json/as_base_class.md

diff --git a/docs/examples/as_base_class.cpp b/docs/examples/as_base_class.cpp
new file mode 100644
index 000000000..6eb2c53a0
--- /dev/null
+++ b/docs/examples/as_base_class.cpp
@@ -0,0 +1,40 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+class base_class_with_shadowed_members
+{
+  public:
+
+    int m_value = 43;
+
+    const char* type_name() const noexcept
+    {
+        return "my_name";
+    }
+};
+
+using json = nlohmann::basic_json <
+             std::map,
+             std::vector,
+             std::string,
+             bool,
+             std::int64_t,
+             std::uint64_t,
+             double,
+             std::allocator,
+             nlohmann::adl_serializer,
+             std::vector<std::uint8_t>,
+             base_class_with_shadowed_members
+             >;
+
+int main()
+{
+    json j;
+
+    //access the shadowing method
+    std::cout << j.type_name() << "\n";
+
+    //access the shadowed method and member variable
+    std::cout << j.as_base_class().type_name() << "\n";
+    std::cout << j.as_base_class().m_value << "\n";
+}
diff --git a/docs/examples/as_base_class.output b/docs/examples/as_base_class.output
new file mode 100644
index 000000000..f9954efa3
--- /dev/null
+++ b/docs/examples/as_base_class.output
@@ -0,0 +1,3 @@
+null
+my_name
+43
diff --git a/docs/mkdocs/docs/api/basic_json/as_base_class.md b/docs/mkdocs/docs/api/basic_json/as_base_class.md
new file mode 100644
index 000000000..84f8d32da
--- /dev/null
+++ b/docs/mkdocs/docs/api/basic_json/as_base_class.md
@@ -0,0 +1,32 @@
+# <small>nlohmann::basic_json::</small>as_base_class
+
+```cpp
+json_base_class_t& as_base_class();
+const json_base_class_t& as_base_class() const;
+```
+
+Returns this object casted to [json_base_class_t](json_base_class_t.md).
+
+## Return value
+
+This object casted to [json_base_class_t](json_base_class_t.md).
+
+## Examples
+
+??? example
+
+    Use `as_base_class` to access shadowed methods and member variables defined in [json_base_class_t](json_base_class_t.md).
+    
+    ```cpp
+    --8<-- "examples/as_base_class.cpp"
+    ```
+    
+    Output:
+    
+    ```json
+    --8<-- "examples/as_base_class.output"
+    ```
+
+## Version history
+
+Added in version ???.???.???
diff --git a/docs/mkdocs/docs/api/basic_json/index.md b/docs/mkdocs/docs/api/basic_json/index.md
index fb2be8fef..3aad26b24 100644
--- a/docs/mkdocs/docs/api/basic_json/index.md
+++ b/docs/mkdocs/docs/api/basic_json/index.md
@@ -151,6 +151,7 @@ The class satisfies the following concept requirements:
 - [**array**](array_t.md) (_static_) - explicitly create an array
 - [**binary**](binary.md) (_static_) - explicitly create a binary array
 - [**object**](object_t.md) (_static_) - explicitly create an object
+- [**as_base_class**](as_base_class.md) - cast this object to [json_base_class_t](json_base_class_t.md)
 
 ### Object inspection
 
diff --git a/docs/mkdocs/mkdocs.yml b/docs/mkdocs/mkdocs.yml
index 8319354a4..20425f2fa 100644
--- a/docs/mkdocs/mkdocs.yml
+++ b/docs/mkdocs/mkdocs.yml
@@ -100,6 +100,7 @@ nav:
         - 'accept': api/basic_json/accept.md
         - 'array': api/basic_json/array.md
         - 'array_t': api/basic_json/array_t.md
+        - 'as_base_class' : api/basic_json/as_base_class.md
         - 'at': api/basic_json/at.md
         - 'back': api/basic_json/back.md
         - 'begin': api/basic_json/begin.md
diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp
index a3c0af1e0..18a916c93 100644
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -5155,6 +5155,16 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     }
 
     /// @}
+
+    json_base_class_t& as_base_class()
+    {
+        return static_cast<json_base_class_t&>(*this);
+    }
+
+    const json_base_class_t& as_base_class() const
+    {
+        return static_cast<const json_base_class_t&>(*this);
+    }
 };
 
 /// @brief user-defined to_string function for JSON values
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 073070a41..92f5d4ebb 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -24379,6 +24379,16 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     }
 
     /// @}
+
+    json_base_class_t& as_base_class()
+    {
+        return static_cast<json_base_class_t&>(*this);
+    }
+
+    const json_base_class_t& as_base_class() const
+    {
+        return static_cast<const json_base_class_t&>(*this);
+    }
 };
 
 /// @brief user-defined to_string function for JSON values