Basic compilation of json to C++ working

Author: lefticus

.clang-tidy

@@ -13,6 +13,7 @@ Checks: "*,
         -readability-avoid-const-params-in-decls,
         -cppcoreguidelines-non-private-member-variables-in-classes,
         -misc-non-private-member-variables-in-classes,
+        -misc-no-recursion
 "
 WarningsAsErrors: ''
 HeaderFilterRegex: ''

src/main.cpp

@@ -1,11 +1,11 @@
-#include <functional>
-#include <iostream>
 #include <filesystem>
 #include <fstream>
+#include <functional>
+#include <iostream>
 
 #include <docopt/docopt.h>
-#include <spdlog/spdlog.h>
 #include <nlohmann/json.hpp>
+#include <spdlog/spdlog.h>
 
 static constexpr auto USAGE =
   R"(json_compiler
@@ -19,13 +19,71 @@ static constexpr auto USAGE =
           --version     Show version.
 )";
 
+std::string to_string(const nlohmann::json &value, std::size_t &obj_count, std::vector<std::string> &lines)
+{
+  const auto current_object_number = obj_count++;
+
+  const auto json_string = [](const auto &str) { return fmt::format("R\"json_string({})json_string\"", str); };
+
+  if (value.is_object()) {
+    std::vector<std::string> pairs;
+    for (auto itr = value.begin(); itr != value.end(); ++itr) {
+      pairs.push_back(fmt::format(
+        "value_pair_t{{std::string_view{{{}}}, {}}},", json_string(itr.key()), to_string(*itr, obj_count, lines)));
+    }
+
+    lines.push_back(fmt::format(
+      "static constexpr std::array<value_pair_t, {}> object_data_{} = {{", pairs.size(), current_object_number));
+
+    std::transform(pairs.begin(), pairs.end(), std::back_inserter(lines), [](const auto &pair) {
+      return fmt::format("  {}", pair);
+    });
+
+    lines.emplace_back("};");
+
+    return fmt::format("json{{object_data_{}}}", current_object_number);
+  } else if (value.is_array()) {
+    std::vector<std::string> entries;
+    std::transform(value.begin(), value.end(), std::back_inserter(entries), [&](const auto &child) {
+      return fmt::format("{},", to_string(child, obj_count, lines));
+    });
+
+
+    lines.push_back(
+      fmt::format("static constexpr std::array<json, {}> object_data_{} = {{", entries.size(), current_object_number));
+
+    std::transform(entries.begin(), entries.end(), std::back_inserter(lines), [](const auto &entry) {
+      return fmt::format("  {}", entry);
+    });
+
+    lines.emplace_back("};");
+
+    return fmt::format("json{{object_data_{}}}", current_object_number);
+
+
+  } else if (value.is_number_float()) {
+    return fmt::format("json{{data_t{{double{{{}}}}}}}", value.get<double>());
+  } else if (value.is_number_unsigned()) {
+    return fmt::format("json{{data_t{{std::uint64_t{{{}}}}}}}", value.get<std::uint64_t>());
+  } else if (value.is_number() && !value.is_number_unsigned()) {
+    return fmt::format("json{{data_t{{std::int64_t{{{}}}}}}}", value.get<std::uint64_t>());
+  } else if (value.is_boolean()) {
+    return fmt::format("json{{data_t{{bool{{{}}}}}}}", value.get<bool>());
+  } else if (value.is_string()) {
+    return fmt::format("json{{data_t{{std::string_view{{{}}}}}}}", json_string(value.get<std::string>()));
+  }
+
+  return "unhandled";
+}
+
+
 int main(int argc, const char **argv)
 {
   try {
     std::map<std::string, docopt::value> args = docopt::docopt(USAGE,
       { std::next(argv), std::next(argv, argc) },
       true,// show help if requested
-      "json_compiler 0.1");// version string
+      "json_compiler 0.0.1");// version string
 
     std::filesystem::path filename = args.at("<file_name>").asString();
     spdlog::info("Loading file: '{}'", filename.native());
@@ -37,6 +95,15 @@ int main(int argc, const char **argv)
     spdlog::info("File loaded");
 
 
+    std::size_t obj_count{ 0 };
+    std::vector<std::string> lines;
+
+    const auto str = to_string(document, obj_count, lines);
+
+    for (const auto &line : lines) { std::cout << line << '\n'; }
+
+    std::cout << "static constexpr auto document = " << str << ";\n";
+
   } catch (const std::exception &e) {
     spdlog::error("Unhandled exception in main: {}", e.what());
   }