Adding initial toy_example that shows why reflection is almost frictionless to use.

examples/github_legacy_benchmark.cpp

@@ -0,0 +1,165 @@
+// Legacy approach with performance measurement
+#include <simdjson.h>
+#include <cpr/cpr.h>
+#include <iostream>
+#include <string>
+#include <optional>
+#include <chrono>
+#include <iomanip>
+#include <sstream>
+
+struct GitHubUser {
+    std::string login;
+    int64_t id;
+    std::string name;
+    std::optional<std::string> company;
+    std::optional<std::string> location;
+    int64_t public_repos;
+    int64_t followers;
+};
+
+// Manual parsing function (the old way)
+GitHubUser parse_github_user(const std::string& json_str) {
+    GitHubUser user;
+    
+    simdjson::ondemand::parser parser;
+    simdjson::padded_string json(json_str);
+    simdjson::ondemand::document doc = parser.iterate(json);
+    
+    // Manual field extraction with error checking
+    user.login = std::string(doc["login"].get_string().value());
+    user.id = doc["id"].get_int64().value();
+    user.name = std::string(doc["name"].get_string().value());
+    
+    // Handle optional fields
+    auto company_result = doc["company"];
+    if (!company_result.is_null()) {
+        user.company = std::string(company_result.get_string().value());
+    }
+    
+    auto location_result = doc["location"];
+    if (!location_result.is_null()) {
+        user.location = std::string(location_result.get_string().value());
+    }
+    
+    user.public_repos = doc["public_repos"].get_int64().value();
+    user.followers = doc["followers"].get_int64().value();
+    
+    return user;
+}
+
+// Manual serialization function (the old way)
+std::string serialize_github_user(const GitHubUser& user) {
+    std::ostringstream json;
+    json << "{";
+    json << "\"login\":\"" << user.login << "\",";
+    json << "\"id\":" << user.id << ",";
+    json << "\"name\":\"" << user.name << "\",";
+    
+    if (user.company.has_value()) {
+        json << "\"company\":\"" << *user.company << "\",";
+    } else {
+        json << "\"company\":null,";
+    }
+    
+    if (user.location.has_value()) {
+        json << "\"location\":\"" << *user.location << "\",";
+    } else {
+        json << "\"location\":null,";
+    }
+    
+    json << "\"public_repos\":" << user.public_repos << ",";
+    json << "\"followers\":" << user.followers;
+    json << "}";
+    
+    return json.str();
+}
+
+int main() {
+    std::cout << "📚 Legacy Approach - Deserialization Performance Benchmark\n";
+    std::cout << "=========================================================\n\n";
+    
+    // Fetch data from GitHub API
+    auto response = cpr::Get(
+        cpr::Url{"https://api.github.com/users/lemire"},
+        cpr::Header{{"User-Agent", "simdjson-benchmark"}}
+    );
+    
+    if (response.status_code != 200) {
+        std::cerr << "❌ Failed to fetch data: HTTP " << response.status_code << "\n";
+        return 1;
+    }
+    
+    // Warm up
+    for (int i = 0; i < 100; ++i) {
+        auto user = parse_github_user(response.text);
+    }
+    
+    // Benchmark
+    const int iterations = 10000;
+    auto start = std::chrono::high_resolution_clock::now();
+    
+    for (int i = 0; i < iterations; ++i) {
+        auto user = parse_github_user(response.text);
+        // Prevent optimization
+        if (i == 0) {
+            std::cout << "Parsing: " << user.name << " (@" << user.login << ")\n\n";
+        }
+    }
+    
+    auto end = std::chrono::high_resolution_clock::now();
+    auto duration = std::chrono::duration_cast<std::chrono::microseconds>(end - start);
+    
+    // Calculate performance metrics
+    double time_per_parse = duration.count() / static_cast<double>(iterations);
+    double bytes_per_parse = response.text.size();
+    double gb_per_second = (bytes_per_parse * iterations) / (duration.count() * 1000.0);
+    
+    std::cout << "📊 Deserialization Performance Results:\n";
+    std::cout << "  • JSON size: " << bytes_per_parse << " bytes\n";
+    std::cout << "  • Iterations: " << iterations << "\n";
+    std::cout << "  • Total time: " << duration.count() / 1000.0 << " ms\n";
+    std::cout << "  • Time per deserialization: " << std::fixed << std::setprecision(2) << time_per_parse << " μs\n";
+    std::cout << "  • Deserialization speed: " << std::fixed << std::setprecision(2) << gb_per_second << " GB/s\n";
+    
+    // Now benchmark serialization
+    std::cout << "\n📝 Serialization Performance Benchmark\n";
+    std::cout << "=====================================\n\n";
+    
+    // Parse once to get a user object
+    auto user = parse_github_user(response.text);
+    
+    // Warm up serialization
+    for (int i = 0; i < 100; ++i) {
+        auto json_str = serialize_github_user(user);
+    }
+    
+    // Benchmark serialization
+    start = std::chrono::high_resolution_clock::now();
+    
+    for (int i = 0; i < iterations; ++i) {
+        auto json_str = serialize_github_user(user);
+        // Prevent optimization
+        if (i == 0) {
+            std::cout << "Serialized JSON size: " << json_str.length() << " bytes\n\n";
+        }
+    }
+    
+    end = std::chrono::high_resolution_clock::now();
+    duration = std::chrono::duration_cast<std::chrono::microseconds>(end - start);
+    
+    // Calculate serialization performance metrics
+    time_per_parse = duration.count() / static_cast<double>(iterations);
+    double serialized_size = serialize_github_user(user).length();
+    gb_per_second = (serialized_size * iterations) / (duration.count() * 1000.0);
+    
+    std::cout << "📊 Serialization Performance Results:\n";
+    std::cout << "  • JSON size: " << serialized_size << " bytes\n";
+    std::cout << "  • Iterations: " << iterations << "\n";
+    std::cout << "  • Total time: " << duration.count() / 1000.0 << " ms\n";
+    std::cout << "  • Time per serialization: " << std::fixed << std::setprecision(2) << time_per_parse << " μs\n";
+    std::cout << "  • Serialization speed: " << std::fixed << std::setprecision(2) << gb_per_second << " GB/s\n";
+    std::cout << "\n⚠️  Note: Manual serialization with string concatenation\n";
+    
+    return 0;
+}