allwpilib/upstream_utils/json_patches/0020-Add-array-and-object-factory-functions.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Peter Johnson <johnson.peter@gmail.com>
Date: Fri, 3 Apr 2026 23:05:58 -0700
Subject: [PATCH 20/25] Add array and object factory functions

---
 json.h | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/json.h b/json.h
index e52435a79ee7537928ba59fb146f635fc8511bfc..6a52615ab3e1799ebcf51a3b5ca445b1e2e64b97 100644
--- a/json.h
+++ b/json.h
@@ -19,6 +19,8 @@
 
 #include <string>
 #include <string_view>
+#include <tuple>
+#include <utility>
 #include <vector>
 
 #include "wpi/util/StringMap.hpp"
@@ -53,6 +55,13 @@ concept HasJsonDeserializer = requires (json& j, const json& cj, const T& val) {
     typename json_serializer<typename std::remove_cvref_t<T>>;
     { json_serializer<typename std::remove_cvref_t<T>>::from(cj) } -> std::convertible_to<typename std::remove_cvref_t<T>>;
 };
+
+template <typename F, typename Tuple, size_t... I>
+void apply_pairs_helper(F&& f, Tuple&& t, std::index_sequence<I...>) {
+    // This fold expression creates a sequence of calls to f for each pair
+    (f(std::get<I * 2>(std::forward<Tuple>(t)),
+       std::get<I * 2 + 1>(std::forward<Tuple>(t))), ...);
+}
 }  // namespace detail
 
 class json
@@ -275,6 +284,27 @@ class json
     void set_array();
     void set_object();
 
+    template <typename... Args>
+    static json array(Args&&... args) {
+        json j;
+        j.set_array();
+        (j.array_value.emplace_back(std::forward<Args>(args)), ...);
+        return j;
+    }
+
+    template <typename... Args>
+    static json object(Args&&... args) {
+        json j;
+        j.set_object();
+        detail::apply_pairs_helper(
+            [&](auto&& key, auto&& value) {
+                j.object_value[std::forward<decltype(key)>(key)] = std::forward<decltype(value)>(value);
+            },
+            std::forward_as_tuple(args...),
+            std::make_index_sequence<sizeof...(Args) / 2>{});
+        return j;
+    }
+
     std::string to_string() const;
     std::string to_string_pretty() const;