Примеры Carbon

// Carbon Hello World Examples

// 1. Basic Hello World
package Main;

import Library;

fn Main() -> i32 {
  Print("Hello, World!\n");
  return 0;
}

// 2. Hello World with variables and types
fn HelloWorldWithVariables() {
  // String literals and variables
  var message1: String = "Hello, World!";
  var message2: String = "Hello, Carbon!";

  Print("{0}\n", message1);
  Print("{0}\n", message2);

  // Basic data types
  var integer: i32 = 42;
  var unsigned_integer: u32 = 100;
  var floating_point: f64 = 3.14159;
  var is_boolean: bool = true;
  var character: u8 = 'A';

  Print("Integer: {0}\n", integer);
  Print("Unsigned: {0}\n", unsigned_integer);
  Print("Float: {0}\n", floating_point);
  Print("Boolean: {0}\n", is_boolean);
  Print("Character: {0}\n", character);
}

// 3. Hello World with functions
fn SayHello() -> String {
  return "Hello, World!";
}

fn GreetUser(name: String) -> String {
  // String interpolation
  return "Hello, {0}!".format(name);
}

fn HelloWorldWithFunctions() {
  Print("{0}\n", SayHello());
  Print("{0}\n", GreetUser("Carbon"));
}

// 4. Hello World with classes
class User {
  var name: String;
  var age: i32;

  // Constructor
  fn Create(n: String, a: i32) -> Self {
    return {.name = n, .age = a};
  }

  // Method
  fn Greet(self: Self) {
    Print("Hello, {0}! You are {1} years old.\n", self.name, self.age);
  }
}

fn HelloWorldWithClasses() {
  var user = User.Create("Alice", 30);
  user.Greet();
}

// 5. Hello World with generics
fn PrintAndReturn[T:! Type](value: T) -> T {
  Print("Value: {0}\n", value);
  return value;
}

fn HelloWorldWithGenerics() {
  var int_result = PrintAndReturn(42);
  var string_result = PrintAndReturn("Hello, Carbon!");
  var bool_result = PrintAndReturn(true);

  Print("Returned: {0}, {1}, {2}\n", int_result, string_result, bool_result);
}

// 6. Hello World with templates
template HelloString {
  fn Get() -> String {
    return "Hello from template!";
  }
}

template HelloNumber {
  fn Get() -> i32 {
    return 42;
  }
}

fn HelloWorldWithTemplates() {
  Print("{0}\n", HelloString.Get());
  Print("{0}\n", HelloNumber.Get());
}

// 7. Hello World with interfaces
interface Greetable {
  fn Greet(self: Self);
}

class FriendlyUser {
  extends Greetable;

  var name: String;

  fn Create(n: String) -> Self {
    return {.name = n};
  }

  fn Greet(self: Self) {
    Print("Friendly hello, {0}!\n", self.name);
  }
}

fn HelloWorldWithInterfaces() {
  var user = FriendlyUser.Create("Bob");
  user.Greet();
}

// 8. Hello World with optional types
fn FindGreeting(id: i32) -> Optional(String) {
  match (id) {
    case 1 => { return "Hello"; }
    case 2 => { return "Hola"; }
    case 3 => { return "Bonjour"; }
    case _ => { return {}; }
  }
}

fn HelloWorldWithOptionals() {
  var greeting1 = FindGreeting(1);
  var greeting2 = FindGreeting(99);

  match (greeting1) {
    case Some(g) => { Print("Found: {0}\n", g); }
    case None => { Print("Not found\n"); }
  }

  match (greeting2) {
    case Some(g) => { Print("Found: {0}\n", g); }
    case None => { Print("Using default greeting\n"); }
  }
}

// 9. Hello World with pattern matching
fn DescribeNumber(n: i32) -> String {
  match (n) {
    case 0 => { return "Zero"; }
    case 1...9 => { return "Single digit"; }
    case 10...99 => { return "Two digits"; }
    case _ => { return "Many digits"; }
  }
}

fn HelloWorldWithPatternMatching() {
  var numbers = [0, 5, 15, 123];
  for (var n in numbers) {
    Print("{0}: {1}\n", n, DescribeNumber(n));
  }
}

// 10. Hello World with error handling
class GreetingError {
  var message: String;

  fn Create(msg: String) -> Self {
    return {.message = msg};
  }
}

fn CreateGreeting(name: String, age: i32) -> Result(String, GreetingError) {
  if (name.empty()) {
    return Error(GreetingError.Create("Empty name"));
  }
  if (age <= 0) {
    return Error(GreetingError.Create("Invalid age"));
  }

  return Ok("Hello, {0} (age {1})!".format(name, age));
}

fn HelloWorldWithErrorHandling() {
  var result1 = CreateGreeting("Alice", 25);
  var result2 = CreateGreeting("", 30);

  match (result1) {
    case Ok(greeting) => { Print("Success: {0}\n", greeting); }
    case Error(err) => { Print("Error: {0}\n", err.message); }
  }

  match (result2) {
    case Ok(greeting) => { Print("Success: {0}\n", greeting); }
    case Error(err) => { Print("Error: {0}\n", err.message); }
  }
}

// 11. Hello World with collections
fn HelloWorldWithCollections() {
  // Array
  var greetings: [String] = ["Hello", "Hola", "Bonjour", "Ciao"];

  Print("Array greetings:\n");
  for (var greeting in greetings) {
    Print("{0}, World!\n", greeting);
  }

  // Vector (dynamic array)
  var dynamic_greetings: Vector(String) = {};
  dynamic_greetings.append("Hi");
  dynamic_greetings.append("Hey");
  dynamic_greetings.append("Yo");

  Print("\nDynamic greetings:\n");
  for (var greeting in dynamic_greetings) {
    Print("{0}, World!\n", greeting);
  }

  // Map
  var language_greetings: Map(String, String) = {};
  language_greetings["english"] = "Hello";
  language_greetings["spanish"] = "Hola";
  language_greetings["french"] = "Bonjour";

  Print("\nLanguage greetings:\n");
  for (var [language, greeting] in language_greetings) {
    Print("{0}: {1}\n", language, greeting);
  }
}

// 12. Hello World with modern features
fn HelloWorldWithModernFeatures() {
  // Auto type inference
  var inferred = 42;  // inferred as i32
  var message = "Hello, Modern Carbon!";  // inferred as String

  // Type-safe string formatting
  var formatted = "{0} + {1} = {2}".format(inferred, 8, inferred + 8);

  // Lambda functions
  var multiplier = fn(i: i32) -> i32 { return i * 2; };
  var result = multiplier(21);

  // Range-based for loop
  var range = 1...5;
  for (var i in range) {
    Print("Square of {0}: {1}\n", i, i * i);
  }

  Print("{0}\n", formatted);
  Print("Lambda result: {0}\n", result);
}

// Main function demonstrating all examples
fn Main() -> i32 {
  Print("=== Carbon Hello World Examples ===\n\n");

  Print("1. Basic Hello World:\n");
  HelloWorldWithVariables();
  Print("\n");

  Print("2. Functions:\n");
  HelloWorldWithFunctions();
  Print("\n");

  Print("3. Classes:\n");
  HelloWorldWithClasses();
  Print("\n");

  Print("4. Generics:\n");
  HelloWorldWithGenerics();
  Print("\n");

  Print("5. Templates:\n");
  HelloWorldWithTemplates();
  Print("\n");

  Print("6. Interfaces:\n");
  HelloWorldWithInterfaces();
  Print("\n");

  Print("7. Optionals:\n");
  HelloWorldWithOptionals();
  Print("\n");

  Print("8. Pattern Matching:\n");
  HelloWorldWithPatternMatching();
  Print("\n");

  Print("9. Error Handling:\n");
  HelloWorldWithErrorHandling();
  Print("\n");

  Print("10. Collections:\n");
  HelloWorldWithCollections();
  Print("\n");

  Print("11. Modern Features:\n");
  HelloWorldWithModernFeatures();
  Print("\n");

  Print("=== All Carbon Examples Completed ===\n");

  return 0;
}

// Carbon Type System and Advanced Features

package Main;

import Library;

// 1. Type declarations and aliases
type UserID = u64;
type ProductID = u32;
type Price = f64;

struct Product {
  var id: ProductID;
  var name: String;
  var price: Price;
  var user_id: UserID;
}

fn TypeDeclarations() {
  var product: Product = {
    .id = 1001,
    .name = "Laptop",
    .price = 999.99,
    .user_id = 12345
  };

  Print("Product: {0}, Price: {1}, User ID: {2}\n",
        product.name, product.price, product.user_id);
}

// 2. Smart pointers and memory safety
interface IDisposable {
  fn Dispose(self: Self);
}

class SmartPointer(T:! Type) {
  extends IDisposable;

  var ptr: *T;
  var allocated: bool;

  // Constructor
  fn Create(ptr: *T) -> Self {
    return {
      .ptr = ptr,
      .allocated = true
    };
  }

  // Destructor
  fn Dispose(self: Self) {
    if (self.allocated) {
      // In real Carbon, this would deallocate memory
      Print("Deallocating smart pointer\n");
      self.allocated = false;
    }
  }

  // Dereference operator
  fn opDereference(self: Self) -> *T {
    return self.ptr;
  }
}

fn SmartPointers() {
  var value: i32 = 42;
  var smart_ptr = SmartPointer(i32).Create(&value);

  Print("Value via smart pointer: {0}\n", *smart_ptr);

  // Automatic cleanup when smart_ptr goes out of scope
  smart_ptr.Dispose();
}

// 3. Pattern matching advanced features
enum NetworkResponse(T:! Type) {
  Success(T),
  Error(ErrorCode, String),
  Timeout,
  NetworkUnavailable
}

enum ErrorCode {
  NotFound,
  PermissionDenied,
  ServerError,
  InvalidInput
}

fn ProcessNetworkResponse[T:! Type](response: NetworkResponse(T)) {
  match (response) {
    case NetworkResponse.Success(data) => {
      Print("Request succeeded with data: {0}\n", data);
    }
    case NetworkResponse.Error(code, message) => {
      Print("Request failed with error {0}: {1}\n", code, message);
    }
    case NetworkResponse.Timeout => {
      Print("Request timed out\n");
    }
    case NetworkResponse.NetworkUnavailable => {
      Print("Network is unavailable\n");
    }
  }
}

fn AdvancedPatternMatching() {
  var success_response = NetworkResponse(String).Success("Data received");
  var error_response = NetworkResponse(String).Error(
    ErrorCode.NotFound, "Resource not found"
  );
  var timeout_response = NetworkResponse(String).Timeout;

  ProcessNetworkResponse(success_response);
  ProcessNetworkResponse(error_response);
  ProcessNetworkResponse(timeout_response);
}

// 4. Generics and constraints
interface Comparable {
  fn Compare(self: Self, other: Self) -> Ordering;
}

enum Ordering {
  Less,
  Equal,
  Greater
}

class Number {
  extends Comparable;

  var value: f64;

  fn Create(v: f64) -> Self {
    return {.value = v};
  }

  fn Compare(self: Self, other: Self) -> Ordering {
    if (self.value < other.value) { return Ordering.Less; }
    if (self.value == other.value) { return Ordering.Equal; }
    return Ordering.Greater;
  }

  fn opLessThan(self: Self, other: Self) -> bool {
    return self.Compare(other) == Ordering.Less;
  }

  fn opGreaterThan(self: Self, other: Self) -> bool {
    return self.Compare(other) == Ordering.Greater;
  }
}

fn FindMax[T:! Comparable](arr: [T]) -> Optional(T) {
  if (arr.empty()) {
    return {};
  }

  var max_val = arr[0];
  for (var i = 1; i < arr.size(); ++i) {
    if (arr[i] > max_val) {
      max_val = arr[i];
    }
  }

  return max_val;
}

fn GenericsAndConstraints() {
  var numbers: [Number] = {
    Number.Create(3.14),
    Number.Create(1.41),
    Number.Create(2.71),
    Number.Create(1.618)
  };

  match (FindMax(numbers)) {
    case Some(max_num) => {
      Print("Maximum value: {0}\n", max_num.value);
    }
    case None => {
      Print("Empty array\n");
    }
  }
}

// 5. Template metaprogramming
template IsIntegral(T:! Type) {
  const value: bool = T == i8 || T == i16 || T == i32 || T == i64 ||
                      T == u8 || T == u16 || T == u32 || T == u64;
}

template EnableIf(T:! Type, condition: bool) {
  extern if (condition);
}

template Square(T:! Type) {
  extern if IsIntegral(T).value;

  fn Square(x: T) -> T {
    return x * x;
  }
}

template Square(i32) {
  fn Square(x: i32) -> i32 {
    // Specialized version for i32
    Print("Using specialized i32 square\n");
    return x * x;
  }
}

fn TemplateMetaprogramming() {
  var i_result = Square(42);
  // var f_result = Square(3.14);  // Compile error: not integral

  Print("Square of 42: {0}\n", i_result);
}

// 6. Advanced error handling with custom error types
class DatabaseError {
  var code: i32;
  var message: String;
  var details: Optional(String);

  fn Create(c: i32, msg: String, det: Optional(String)) -> Self {
    return {
      .code = c,
      .message = msg,
      .details = det
    };
  }

  fn Format(self: Self) -> String {
    match (self.details) {
      case Some(details) => {
        return "Error {0}: {1} - {2}".format(self.code, self.message, details);
      }
      case None => {
        return "Error {0}: {1}".format(self.code, self.message);
      }
    }
  }
}

fn QueryDatabase(query: String) -> Result(String, DatabaseError) {
  if (query.empty()) {
    return Error(DatabaseError.Create(400, "Empty query", Some("Query cannot be empty")));
  }

  if (query.contains("DROP")) {
    return Error(DatabaseError.Create(403, "Forbidden operation",
      Some("DROP commands are not allowed")));
  }

  // Simulate successful query
  return Ok("Query executed successfully");
}

fn AdvancedErrorHandling() {
  var queries = ["SELECT * FROM users", "DROP TABLE users", ""];

  for (var query in queries) {
    var result = QueryDatabase(query);

    match (result) {
      case Ok(success) => {
        Print("Query '{0}': {1}\n", query, success);
      }
      case Error(db_error) => {
        Print("Query '{0}': {1}\n", query, db_error.Format());
      }
    }
  }
}

// 7. Lambda functions and functional programming
fn FunctionalProgramming() {
  // Lambda with capture
  var multiplier = 3;
  var multiply_fn = fn(x: i32) -> i32 { return x * multiplier; };

  // Lambda as parameter
  fn ApplyOperation(arr: [i32, 5], operation: fn(i32) -> i32) -> [i32, 5] {
    var result: [i32, 5] = {};
    for (var i = 0; i < arr.size(); ++i) {
      result[i] = operation(arr[i]);
    }
    return result;
  }

  var numbers: [i32, 5] = {1, 2, 3, 4, 5};
  var doubled = ApplyOperation(numbers, fn(x: i32) -> i32 { return x * 2; });
  var multiplied = ApplyOperation(numbers, multiply_fn);

  Print("Original: {0}\n", numbers);
  Print("Doubled:  {0}\n", doubled);
  Print("Multiplied by 3: {0}\n", multiplied);
}

// 8. Modules and namespaces
module Math {

  fn Add(a: f64, b: f64) -> f64 {
    return a + b;
  }

  fn Multiply(a: f64, b: f64) -> f64 {
    return a * b;
  }

  module Advanced {
    fn Power(base: f64, exp: i32) -> f64 {
      if (exp == 0) { return 1.0; }
      if (exp < 0) { return 1.0 / Power(base, -exp); }
      return base * Power(base, exp - 1);
    }
  }
}

fn ModulesAndNamespaces() {
  var sum = Math.Add(3.14, 2.71);
  var product = Math.Multiply(4.2, 1.5);
  var power = Math.Advanced.Power(2.0, 8);

  Print("Sum: {0}, Product: {1}, Power: {2}\n", sum, product, power);
}

// 9. Reflection capabilities (conceptual)
interface Reflectable {
  fn GetType() -> String;
  fn GetFields() -> [String];
  fn GetFieldValue(self: Self, field: String) -> String;
}

class ReflectableUser {
  extends Reflectable;

  var name: String;
  var age: i32;
  var email: String;

  fn Create(n: String, a: i32, e: String) -> Self {
    return {
      .name = n,
      .age = a,
      .email = e
    };
  }

  fn GetType() -> String {
    return "ReflectableUser";
  }

  fn GetFields() -> [String] {
    return {"name", "age", "email"};
  }

  fn GetFieldValue(self: Self, field: String) -> String {
    match (field) {
      case "name" => { return self.name; }
      case "age" => { return "{0}".format(self.age); }
      case "email" => { return self.email; }
      case _ => { return "Unknown field"; }
    }
  }
}

fn PrintReflectionInfo[T:! Reflectable](obj: T) {
  Print("Type: {0}\n", obj.GetType());
  Print("Fields:\n");
  for (var field in obj.GetFields()) {
    Print("  {0}: {1}\n", field, obj.GetFieldValue(field));
  }
}

fn Reflection() {
  var user = ReflectableUser.Create("Alice", 30, "[email protected]");
  PrintReflectionInfo(user);
}

// 10. Async/await concepts (future Carbon feature)
class Future(T:! Type) {
  var value: Optional(T);
  var completed: bool;

  fn Create() -> Self {
    return {
      .value = {},
      .completed = false
    };
  }

  fn Set(self: Self, val: T) {
    self.value = val;
    self.completed = true;
  }

  fn Await(self: Self) -> T {
    while (!self.completed) {
      // In real implementation, this would yield to scheduler
      // Simulated busy wait for demonstration
    }
    return self.value.unwrap();
  }
}

fn AsyncConcepts() {
  var future_int = Future(i32).Create();
  var future_string = Future(String).Create();

  // Simulate async operations
  future_int.Set(42);
  future_string.Set("Async result");

  Print("Async int result: {0}\n", future_int.Await());
  Print("Async string result: {0}\n", future_string.Await());
}

// Main function demonstrating all advanced features
fn Main() -> i32 {
  Print("=== Carbon Type System and Advanced Features ===\n\n");

  Print("1. Type Declarations:\n");
  TypeDeclarations();
  Print("\n");

  Print("2. Smart Pointers:\n");
  SmartPointers();
  Print("\n");

  Print("3. Advanced Pattern Matching:\n");
  AdvancedPatternMatching();
  Print("\n");

  Print("4. Generics and Constraints:\n");
  GenericsAndConstraints();
  Print("\n");

  Print("5. Template Metaprogramming:\n");
  TemplateMetaprogramming();
  Print("\n");

  Print("6. Advanced Error Handling:\n");
  AdvancedErrorHandling();
  Print("\n");

  Print("7. Functional Programming:\n");
  FunctionalProgramming();
  Print("\n");

  Print("8. Modules and Namespaces:\n");
  ModulesAndNamespaces();
  Print("\n");

  Print("9. Reflection:\n");
  Reflection();
  Print("\n");

  Print("10. Async Concepts:\n");
  AsyncConcepts();
  Print("\n");

  Print("=== All Advanced Features Completed ===\n");

  return 0;
}

// Carbon Performance and C++ Interoperability

package Main;

import CppLibrary;  // Hypothetical C++ interop library
import Library;

// 1. Performance-critical data structures
class PerformanceVector(T:! Type) {
  var data: *T;
  var size: u64;
  var capacity: u64;

  fn Create(initial_capacity: u64) -> Self {
    return {
      .data = Allocate(T, initial_capacity),
      .size = 0,
      .capacity = initial_capacity
    };
  }

  fn Dispose(self: Self) {
    Deallocate(self.data);
  }

  fn Append(self: Self, item: T) {
    if (self.size >= self.capacity) {
      // Double capacity with efficient reallocation
      var new_capacity = self.capacity * 2;
      var new_data = Allocate(T, new_capacity);

      // Fast memory copy
      for (var i = 0; i < self.size; ++i) {
        new_data[i] = self.data[i];
      }

      Deallocate(self.data);
      self.data = new_data;
      self.capacity = new_capacity;
    }

    self.data[self.size] = item;
    self.size += 1;
  }

  fn opIndex(self: Self, index: u64) -> *T {
    return &self.data[index];
  }

  fn Size(self: Self) -> u64 {
    return self.size;
  }

  fn Capacity(self: Self) -> u64 {
    return self.capacity;
  }
}

fn PerformanceDataStructures() {
  var vec = PerformanceVector(i32).Create(4);

  // Efficient bulk insertion
  for (var i = 0; i < 1000; ++i) {
    vec.Append(i * 2);
  }

  Print("Vector size: {0}, capacity: {1}\n", vec.Size(), vec.Capacity());
  Print("Element 500: {0}\n", *vec[500]);

  vec.Dispose();
}

// 2. Memory pool allocator for performance
class MemoryPool {
  var pool: *u8;
  var pool_size: u64;
  var used: u64;
  var allocations: u64;

  fn Create(size: u64) -> Self {
    return {
      .pool = Allocate(u8, size),
      .pool_size = size,
      .used = 0,
      .allocations = 0
    };
  }

  fn Dispose(self: Self) {
    Deallocate(self.pool);
  }

  fn Allocate(T:! Type)(self: Self, count: u64 = 1) -> *T {
    var size = count * sizeof(T);
    var aligned_size = ((size + 7) / 8) * 8;  // 8-byte alignment

    if (self.used + aligned_size > self.pool_size) {
      return null;  // Pool exhausted
    }

    var ptr = self.pool + self.used;
    self.used += aligned_size;
    self.allocations += 1;

    return ptr as *T;
  }

  fn Reset(self: Self) {
    self.used = 0;
    self.allocations = 0;
  }

  fn Usage(self: Self) -> f64 {
    return (self.used as f64) / (self.pool_size as f64);
  }
}

fn MemoryPoolPerformance() {
  var pool = MemoryPool.Create(1024 * 1024);  // 1MB pool

  // Fast allocation from pool
  var int_array = pool.Allocate(i32, 1000);
  var string_ptr = pool.Allocate(String);

  Print("Pool usage: {0:.2f}%\n", pool.Usage() * 100);
  Print("Allocations: {0}\n", pool.allocations);

  // Reset pool for reuse
  pool.Reset();
  Print("Pool usage after reset: {0:.2f}%\n", pool.Usage() * 100);

  pool.Dispose();
}

// 3. SIMD vectorization support
extern "C++" {
  // SIMD intrinsics interface
  fn simd_add_f32(a: *f32, b: *f32, result: *f32, count: u64);
  fn simd_mul_f32(a: *f32, b: *f32, result: *f32, count: u64);
  fn simd_dot_f32(a: *f32, b: *f32, result: *f32, count: u64);
}

class SIMDVector {
  var data: *f32;
  var size: u64;

  fn Create(n: u64) -> Self {
    return {
      .data = Allocate(f32, n),
      .size = n
    };
  }

  fn Dispose(self: Self) {
    Deallocate(self.data);
  }

  fn Set(self: Self, index: u64, value: f32) {
    self.data[index] = value;
  }

  fn Get(self: Self, index: u64) -> f32 {
    return self.data[index];
  }

  fn Add(self: Self, other: Self, result: Self) {
    simd_add_f32(self.data, other.data, result.data, self.size);
  }

  fn Multiply(self: Self, other: Self, result: Self) {
    simd_mul_f32(self.data, other.data, result.data, self.size);
  }

  fn DotProduct(self: Self, other: Self) -> f64 {
    var result: f32 = 0.0;
    simd_dot_f32(self.data, other.data, &result, self.size);
    return result as f64;
  }
}

fn SIMDPerformance() {
  var size = 1024;  // Must be multiple of SIMD width

  var vec1 = SIMDVector.Create(size);
  var vec2 = SIMDVector.Create(size);
  var result = SIMDVector.Create(size);

  // Initialize vectors
  for (var i = 0; i < size; ++i) {
    vec1.Set(i, i as f32);
    vec2.Set(i, (i * 2) as f32);
  }

  // SIMD operations
  vec1.Add(vec2, result);
  var dot = vec1.DotProduct(vec2);

  Print("SIMD Add result[0]: {0}\n", result.Get(0));
  Print("SIMD Add result[1023]: {0}\n", result.Get(1023));
  Print("SIMD Dot product: {0}\n", dot);

  vec1.Dispose();
  vec2.Dispose();
  result.Dispose();
}

// 4. C++ interoperability examples
extern "C++" {
  // C++ standard library types
  cpp_class std.vector(T) {
    fn size() -> u64;
    fn push_back(value: T);
    fn operator[](index: u64) -> T;
    fn data() -> *T;
  }

  cpp_class std.string {
    fn c_str() -> *char;
    fn size() -> u64;
  }

  // Custom C++ class
  cpp_class CppCalculator {
    fn Create() -> Self;
    fn Add(a: f64, b: f64) -> f64;
    fn Multiply(a: f64, b: f64) -> f64;
    fn GetHistory() -> std.vector(f64);
  }
}

fn CppInterop() {
  // Use C++ std::vector
  var cpp_vec = std.vector(i32).Create();
  cpp_vec.push_back(42);
  cpp_vec.push_back(84);

  Print("C++ vector size: {0}\n", cpp_vec.size());
  Print("C++ vector[0]: {0}\n", cpp_vec[0]);

  // Use C++ std::string
  var cpp_str = std.string.Create("Hello from C++");
  Print("C++ string: {0}\n", cpp_str.c_str());

  // Use custom C++ class
  var calc = CppCalculator.Create();
  var sum = calc.Add(3.14, 2.71);
  var product = calc.Multiply(4.2, 1.5);

  Print("C++ Calculator - Sum: {0}, Product: {1}\n", sum, product);

  var history = calc.GetHistory();
  Print("Calculator history size: {0}\n", history.size());
}

// 5. Zero-cost abstractions
template Container(T:! Type) {
  fn Map(arr: [T], operation: fn(T) -> T) -> [T] {
    var result: [T] = {};
    for (var item in arr) {
      result.push(operation(item));
    }
    return result;
  }

  fn Filter(arr: [T], predicate: fn(T) -> bool) -> [T] {
    var result: [T] = {};
    for (var item in arr) {
      if (predicate(item)) {
        result.push(item);
      }
    }
    return result;
  }

  fn Reduce(arr: [T], initial: T, operation: fn(T, T) -> T) -> T {
    var result = initial;
    for (var item in arr) {
      result = operation(result, item);
    }
    return result;
  }
}

fn ZeroCostAbstractions() {
  var numbers = [1, 2, 3, 4, 5];

  // These compile to highly optimized code
  var doubled = Container(i32).Map(numbers, fn(x: i32) -> i32 { return x * 2; });
  var evens = Container(i32).Filter(numbers, fn(x: i32) -> bool { return x % 2 == 0; });
  var sum = Container(i32).Reduce(numbers, 0, fn(acc: i32, x: i32) -> i32 { return acc + x; });

  Print("Doubled: {0}\n", doubled);
  Print("Evens: {0}\n", evens);
  Print("Sum: {0}\n", sum);
}

// 6. Compile-time computations
const Fib(n: u32) = n <= 1 ? n : Fib(n - 1) + Fib(n - 2);

template CompileTimeFib(n: u32) {
  const value = Fib(n);
}

fn CompileTimeComputations() {
  // Compile-time Fibonacci values
  const fib10 = CompileTimeFib(10).value;
  const fib20 = CompileTimeFib(20).value;

  Print("Fib(10) = {0} (computed at compile time)\n", fib10);
  Print("Fib(20) = {0} (computed at compile time)\n", fib20);

  // Compile-time string operations
  const greeting = "Hello, Carbon!";
  const greeting_length = greeting.size();

  Print("Greeting: {0}\n", greeting);
  Print("Length: {0} (computed at compile time)\n", greeting_length);
}

// 7. Performance measurement utilities
class Timer {
  var start_time: u64;
  var end_time: u64;

  fn Create() -> Self {
    return {
      .start_time = 0,
      .end_time = 0
    };
  }

  fn Start(self: Self) {
    self.start_time = GetCurrentTimeNanos();
  }

  fn Stop(self: Self) {
    self.end_time = GetCurrentTimeNanos();
  }

  fn ElapsedNanos(self: Self) -> u64 {
    return self.end_time - self.start_time;
  }

  fn ElapsedMillis(self: Self) -> f64 {
    return (self.ElapsedNanos() as f64) / 1_000_000.0;
  }

  fn ElapsedSeconds(self: Self) -> f64 {
    return (self.ElapsedNanos() as f64) / 1_000_000_000.0;
  }
}

extern "C++" {
  fn GetCurrentTimeNanos() -> u64;
}

fn PerformanceMeasurement() {
  var timer = Timer.Create();

  // Measure allocation performance
  timer.Start();
  var pool = MemoryPool.Create(10 * 1024 * 1024);  // 10MB

  for (var i = 0; i < 100_000; ++i) {
    var ptr = pool.Allocate(i64);
    if (ptr != null) {
      *ptr = i;
    }
  }

  timer.Stop();

  Print("100k allocations from pool: {0:.3f} ms\n", timer.ElapsedMillis());
  Print("Pool usage: {0:.2f}%\n", pool.Usage() * 100);

  pool.Dispose();
}

// 8. Parallel processing concepts
class ThreadPool {
  var threads: *Thread;
  var thread_count: u64;
  var work_queue: WorkQueue;

  fn Create(count: u64) -> Self {
    return {
      .threads = Allocate(Thread, count),
      .thread_count = count,
      .work_queue = WorkQueue.Create()
    };
  }

  fn Dispose(self: Self) {
    // Wait for all threads to finish
    // Clean up resources
    Deallocate(self.threads);
  }

  fn SubmitWork(self: Self, work: fn()) -> Future(void) {
    // Submit work to queue and return future
    // Implementation would involve thread synchronization
  }
}

fn ParallelProcessing() {
  var pool = ThreadPool.Create(4);

  // Parallel computation example
  var results = [Future(void)]{};

  for (var i = 0; i < 8; ++i) {
    var future = pool.SubmitWork(fn() {
      // Simulate work
      Print("Work item {0} executing\n", i);
    });
    results.push(future);
  }

  // Wait for all work to complete
  for (var future in results) {
    future.Await();
  }

  pool.Dispose();
}

// Main function demonstrating all performance features
fn Main() -> i32 {
  Print("=== Carbon Performance and Interop Examples ===\n\n");

  Print("1. Performance Data Structures:\n");
  PerformanceDataStructures();
  Print("\n");

  Print("2. Memory Pool Performance:\n");
  MemoryPoolPerformance();
  Print("\n");

  Print("3. SIMD Performance:\n");
  SIMDPerformance();
  Print("\n");

  Print("4. C++ Interoperability:\n");
  CppInterop();
  Print("\n");

  Print("5. Zero-Cost Abstractions:\n");
  ZeroCostAbstractions();
  Print("\n");

  Print("6. Compile-Time Computations:\n");
  CompileTimeComputations();
  Print("\n");

  Print("7. Performance Measurement:\n");
  PerformanceMeasurement();
  Print("\n");

  Print("8. Parallel Processing:\n");
  ParallelProcessing();
  Print("\n");

  Print("=== All Performance Examples Completed ===\n");

  return 0;
}