What is Flex?
I have designed a theoretical programming language called Flex which consists of interesting new and some older but mature concepts. Flex is supposed to be a typed language with all the properties I‘d love to see in a general-purpose programming language. It should be easy to learn, implement various paradigms that can be smartly combined, create efficient code, and support different backends. Needless to say that I borrowed a lot of features from existing languages.
Flex is a programming language designed to address the evolving needs of modern software development. Built around the principle of extensible simplicity, Flex tries to combine the performance of systems languages with the expressiveness of high-level languages, while maintaining an intuitive syntax that makes it accessible to developers of all skill levels.
Core Philosophy
At its heart, Flex embodies three fundamental principles:
Kernel-Based Extensibility: Unlike traditional languages that are fixed in their capabilities, Flex features a minimal core kernel that can be dynamically extended through additional specialized kernels. This allows the language to grow and adapt to new domains without breaking existing code or requiring language redesigns.
Paradigm Harmony: Rather than forcing developers to choose between programming paradigms, Flex seamlessly integrates object-oriented, functional, concurrent, generic, and metaprogramming approaches. This integration eliminates paradigm drift and allows developers to use the most appropriate approach for each problem.
Performance Without Compromise: Flex delivers native-level performance through multiple compilation backends while maintaining memory safety and developer productivity. The language compiles to LLVM IR, WebAssembly, and its own virtual machine, ensuring optimal performance across different deployment targets.
Key Benefits
Developer Productivity
Flex reduces development time through its intuitive syntax, comprehensive standard library, and powerful metaprogramming capabilities. The language's design minimizes cognitive load by using consistent patterns across different features and paradigms. Automatic memory management handles the common cases while still providing manual control when needed for performance-critical sections.
Future-Proof Architecture
The kernel-based extension system means that Flex can evolve with changing technology landscapes. When new domains emerge—whether in AI, quantum computing, or other fields—new kernels can be developed to provide first-class language support without requiring core language changes.
Unmatched Versatility
Flex excels across diverse application domains. It can build high-performance system software, create modern web applications, develop AI and machine learning systems, implement embedded software, and construct large-scale distributed systems—all using the same language with domain-specific kernels providing specialized capabilities.
Enterprise-Ready Reliability
The language includes various error handling mechanisms, strong static typing with inference, and extensive compile-time checking. These features catch errors early in the development cycle, reducing debugging time and improving software reliability in production environments.
Fundamental Structure
The Kernel Architecture
Flex's architecture consists of a minimal core kernel that provides essential language constructs like variables, functions, control flow, and basic types. This core is then extended through specialized kernels:
- AIKernel provides native support for machine learning, neural networks, and large language model integration
- WebKernel offers comprehensive web development capabilities including HTTP servers, WebSocket support, and API frameworks
- SystemKernel enables low-level system programming with unsafe operations and hardware interfaces
- ConcurrencyKernel delivers advanced parallel programming patterns and actor-based systems
This modular approach means developers only include the capabilities they need, keeping applications lean while providing access to powerful domain-specific features.
Compilation Pipeline
Flex employs a sophisticated compilation pipeline built around ANTLR v4 grammar processing. The compiler performs lexical analysis, parsing, semantic analysis, and optimization before generating code for multiple backends. This multi-target approach ensures that Flex applications can run efficiently on servers, in browsers, on mobile devices, and in embedded systems.
Type System Excellence
The language features a powerful static type system with intelligent inference that reduces verbosity while maintaining safety. Generic programming capabilities allow for highly reusable code, while the type system prevents common programming errors at compile time. Optional types handle null safety elegantly, and the Result type provides robust error handling without exceptions' performance overhead.
Modern Development Alignment
AI-First Design
Recognizing the central role of artificial intelligence in modern software, Flex provides built-in support for AI and generative AI applications. The language can seamlessly integrate with large language models, perform tensor operations, and handle neural network computations as first-class operations rather than through external libraries.
Cloud-Native Capabilities
Flex is designed for cloud-native development with built-in support for microservices, containerization, and distributed systems. The language's concurrency model and networking capabilities make it ideal for building scalable cloud applications.
Developer Experience Focus
Every aspect of Flex prioritizes developer experience. The language features excellent tooling support, comprehensive documentation generation, integrated testing frameworks, and powerful debugging capabilities. The syntax is designed to be readable and writable, reducing the learning curve for new team members.
Performance Characteristics
Flex delivers performance comparable to C and C++ while providing memory safety guarantees. The language achieves this through:
- Zero-cost abstractions that compile away at runtime
- Intelligent memory management that combines automatic garbage collection with manual control options
- Advanced optimization through LLVM integration and profile-guided optimization
- SIMD support for vectorized operations
- Compile-time computation that moves work from runtime to build time
Ecosystem and Interoperability
The language provides interoperability with existing codebases through comprehensive foreign function interfaces for C, C++, and other languages. This allows organizations to gradually adopt Flex while leveraging existing investments in other technologies.
The standard library is extensive and covers everything from basic data structures to advanced networking, cryptography, and AI operations. The package management system makes it easy to share and reuse code across projects and organizations.
Conclusion
Flex represents a new programming language that prioritizes both developer productivity and system performance. Its kernel-based architecture ensures longevity and adaptability, while its comprehensive feature set makes it suitable for virtually any software development task. By eliminating the traditional trade-offs between ease of use, performance, and capability, Flex enables developers to focus on solving problems rather than wrestling with language limitations.
Whether you're building the next generation of AI applications, creating high-performance system software, or developing modern web services, Flex provides the tools, performance, and flexibility needed to succeed in today's rapidly evolving technology landscape.
In the remainder of this post you‘ll find the developer guide as a Markdown document.
Note: The language specification below is neither sound and error-free nor do I claim all language features are consistent, correct, and should be implemented in all details. Implementing such a language is far from being trivial or easy. For example, only basic kernels would be available in the beginning.
—- cut here —-
# Flex - Developer Guide
## Table of Contents
1. [Getting Started](#getting-started)
2. [Basic Syntax and Types](#basic-syntax-and-types)
3. [Control Flow](#control-flow)
4. [Functions and Closures](#functions-and-closures)
5. [Object-Oriented Programming](#object-oriented-programming)
6. [Functional Programming](#functional-programming)
7. [Generic Programming](#generic-programming)
8. [Metaprogramming](#metaprogramming)
9. [Concurrency and Parallelism](#concurrency-and-parallelism)
10. [Module System](#module-system)
11. [Kernel Extensions](#kernel-extensions)
12. [AI and GenAI Integration](#ai-and-genai-integration)
13. [API Development](#api-development)
14. [System Programming](#system-programming)
15. [Error Handling](#error-handling)
16. [Standard Library](#standard-library)
17. [Advanced Features](#advanced-features)
---
## Getting Started
### Installation and Setup
```bash
# Install Flex compiler
curl -sSf https://install.flex-lang.org | sh
# Verify installation
flex --version
# Create a new project
flex new my_project
cd my_project
# Build and run
flex build
flex run
```
### Your First Flex Program
```flex
// hello.flex
fn main() {
println("Hello, Flex!")
}
```
Running it:
```bash
flex run hello.flex
```
---
## Basic Syntax and Types
### Variables and Constants
```flex
// Immutable variables (default)
let name = "Alice" // Type inferred as String
let age: Int = 25 // Explicit type annotation
let height = 5.8 // Type inferred as Float
// Mutable variables
var counter = 0 // Can be modified
var scores: List<Int> = [] // Mutable list
// Constants (compile-time)
const PI = 3.14159
const MAX_USERS = 1000
```
### Primitive Types
```flex
// Integers
let small: Int8 = 127
let medium: Int32 = 2_147_483_647
let large: Int64 = 9_223_372_036_854_775_807
let unsigned: UInt32 = 4_294_967_295
// Floating point
let precise: Float32 = 3.14
let double: Float64 = 2.718281828
// Boolean
let is_active: Bool = true
let is_complete = false
// Character and String
let letter: Char = 'A'
let message: String = "Hello, World!"
let multiline = """
This is a
multiline string
"""
// Optional types
let maybe_value: Optional<Int> = Some(42)
let empty_value: Optional<Int> = None
```
### Collections
```flex
// Arrays (fixed size)
let numbers: Array<Int, 5> = [1, 2, 3, 4, 5]
// Lists (dynamic)
let fruits = ["apple", "banana", "orange"]
var shopping_list: List<String> = []
shopping_list.push("milk")
// Maps
let scores = {
"Alice": 95,
"Bob": 87,
"Charlie": 92
}
// Sets
let unique_numbers = {1, 2, 3, 4, 5}
// Tuples
let point: (Int, Int) = (10, 20)
let person = ("Alice", 25, true) // (String, Int, Bool)
```
---
## Control Flow
### Conditional Statements
```flex
// Basic if-else
let score = 85
if score >= 90 {
println("Excellent!")
} else if score >= 80 {
println("Good!")
} else if score >= 70 {
println("Average")
} else {
println("Needs improvement")
}
// Conditional expressions
let grade = if score >= 90 { "A" } else if score >= 80 { "B" } else { "C" }
// Guard clauses
fn process_user(user: Optional<User>) {
guard let user = user else {
println("No user provided")
return
}
// Process user...
}
```
### Loops
```flex
// For loops
for i in 0..10 {
println("Number: {i}")
}
// For-in loops
let numbers = [1, 2, 3, 4, 5]
for num in numbers {
println("Value: {num}")
}
// For with index
for (index, value) in numbers.enumerate() {
println("Index {index}: {value}")
}
// While loops
var count = 0
while count < 5 {
println("Count: {count}")
count += 1
}
// Loop with break and continue
for i in 0..100 {
if i % 2 == 0 {
continue
}
if i > 50 {
break
}
println("Odd number: {i}")
}
```
### Match Expressions
```flex
// Basic matching
let day = "Monday"
let mood = match day {
"Monday" => "Tired",
"Friday" => "Excited",
"Saturday" | "Sunday" => "Relaxed",
_ => "Normal"
}
// Matching with guards
let number = 42
match number {
n if n < 0 => println("Negative"),
n if n == 0 => println("Zero"),
n if n > 100 => println("Large"),
n => println("Normal: {n}")
}
// Destructuring match
let point = (3, 4)
match point {
(0, 0) => println("Origin"),
(x, 0) => println("On X-axis: {x}"),
(0, y) => println("On Y-axis: {y}"),
(x, y) => println("Point: ({x}, {y})")
}
// Matching optionals
let maybe_number: Optional<Int> = Some(42)
match maybe_number {
Some(value) => println("Got value: {value}"),
None => println("No value")
}
```
### Structured Matching
```flex
// Matching structs
struct User {
name: String,
age: Int,
is_admin: Bool
}
let user = User { name: "Alice", age: 25, is_admin: true }
match user {
User { name: "Alice", is_admin: true, .. } => println("Admin Alice"),
User { age, .. } if age < 18 => println("Minor user"),
User { name, age, is_admin: false } => println("Regular user {name}, age {age}"),
_ => println("Unknown user type")
}
// Matching enums
enum Result<T, E> {
Ok(T),
Err(E)
}
let result: Result<Int, String> = Ok(42)
match result {
Ok(value) => println("Success: {value}"),
Err(error) => println("Error: {error}")
}
```
---
## Functions and Closures
### Basic Functions
```flex
// Simple function
fn add(a: Int, b: Int) -> Int {
a + b
}
// Function with default parameters
fn greet(name: String, greeting: String = "Hello") -> String {
"{greeting}, {name}!"
}
// Variadic functions
fn sum(numbers: ...Int) -> Int {
numbers.fold(0, +)
}
let total = sum(1, 2, 3, 4, 5) // 15
// Named parameters
fn create_user(name: String, age: Int, email: String = "") -> User {
User { name, age, email }
}
let user = create_user(name: "Alice", age: 25, email: "alice@example.com")
```
### Higher-Order Functions
```flex
// Functions as parameters
fn apply_operation(a: Int, b: Int, op: (Int, Int) -> Int) -> Int {
op(a, b)
}
let result = apply_operation(5, 3, add)
// Functions as return values
fn make_multiplier(factor: Int) -> (Int) -> Int {
fn(x: Int) -> Int {
x * factor
}
}
let double = make_multiplier(2)
let result = double(5) // 10
```
### Closures
```flex
// Basic closures
let numbers = [1, 2, 3, 4, 5]
// Short closure syntax
let doubled = numbers.map(|x| x * 2)
let evens = numbers.filter(|x| x % 2 == 0)
// Multi-line closures
let processed = numbers.map(|x| {
let squared = x * x
let doubled = squared * 2
doubled + 1
})
// Capturing environment
let multiplier = 3
let multiply_by_three = |x| x * multiplier
// Mutable captures
var counter = 0
let increment = || {
counter += 1
counter
}
```
### Function Overloading
```flex
// Overloading by parameter count
fn print(value: String) {
println(value)
}
fn print(value: String, prefix: String) {
println("{prefix}: {value}")
}
// Overloading by type
fn convert(value: Int) -> String {
value.to_string()
}
fn convert(value: Float) -> String {
value.to_string()
}
```
---
## Object-Oriented Programming
### Classes and Objects
```flex
// Basic class
class Person {
// Fields
private name: String
private age: Int
// Constructor
init(name: String, age: Int) {
self.name = name
self.age = age
}
// Methods
method get_name() -> String {
self.name
}
method celebrate_birthday() {
self.age += 1
println("{self.name} is now {self.age} years old!")
}
// Static method
static method create_adult(name: String) -> Person {
Person(name, 18)
}
}
// Creating objects
let person = Person("Alice", 25)
person.celebrate_birthday()
let adult = Person.create_adult("Bob")
```
### Inheritance
```flex
// Base class
class Animal {
protected name: String
init(name: String) {
self.name = name
}
virtual method make_sound() -> String {
"Some generic sound"
}
method get_name() -> String {
self.name
}
}
// Derived class
class Dog extends Animal {
private breed: String
init(name: String, breed: String) {
super(name)
self.breed = breed
}
override method make_sound() -> String {
"Woof!"
}
method get_breed() -> String {
self.breed
}
}
let dog = Dog("Rex", "Golden Retriever")
println(dog.make_sound()) // "Woof!"
```
### Interfaces and Traits
```flex
// Interface definition
trait Drawable {
method draw() -> String
method area() -> Float
}
// Default implementations
trait Printable {
method print() {
println(self.to_string())
}
// Required method
method to_string() -> String
}
// Implementing traits
class Circle implements Drawable, Printable {
private radius: Float
init(radius: Float) {
self.radius = radius
}
method draw() -> String {
"Drawing a circle with radius {self.radius}"
}
method area() -> Float {
PI * self.radius * self.radius
}
method to_string() -> String {
"Circle(radius: {self.radius})"
}
}
let circle = Circle(5.0)
circle.print() // Uses default implementation
println(circle.area())
```
### Properties and Accessors
```flex
class Temperature {
private celsius: Float
init(celsius: Float) {
self.celsius = celsius
}
// Computed property
property fahrenheit: Float {
get { self.celsius * 9.0 / 5.0 + 32.0 }
set(value) { self.celsius = (value - 32.0) * 5.0 / 9.0 }
}
// Read-only property
property kelvin: Float {
get { self.celsius + 273.15 }
}
}
let temp = Temperature(25.0)
println(temp.fahrenheit) // 77.0
temp.fahrenheit = 86.0
println(temp.celsius) // 30.0
```
---
## Functional Programming
### Immutability and Pure Functions
```flex
// Pure functions (no side effects)
fn add(a: Int, b: Int) -> Int {
a + b // No mutation, no I/O
}
// Immutable data structures
let original_list = [1, 2, 3]
let new_list = original_list.append(4) // Returns new list
// original_list is unchanged
// Persistent data structures
let map1 = {"a": 1, "b": 2}
let map2 = map1.insert("c", 3) // Returns new map
// map1 is unchanged
```
### Function Composition
```flex
// Function composition operator
let add_one = |x| x + 1
let multiply_two = |x| x * 2
let square = |x| x * x
// Compose functions
let composed = add_one >> multiply_two >> square
let result = composed(3) // ((3 + 1) * 2)² = 64
// Pipeline operator
let result = 5
|> add_one
|> multiply_two
|> square
```
### Monads and Functors
```flex
// Optional monad
let maybe_number: Optional<Int> = Some(42)
let result = maybe_number
.map(|x| x * 2)
.flat_map(|x| if x > 50 { Some(x) } else { None })
.unwrap_or(0)
// Result monad for error handling
fn divide(a: Float, b: Float) -> Result<Float, String> {
if b == 0.0 {
Err("Division by zero")
} else {
Ok(a / b)
}
}
let result = divide(10.0, 2.0)
.map(|x| x * 2)
.and_then(|x| divide(x, 3.0))
.unwrap_or(0.0)
```
### Lazy Evaluation
```flex
// Lazy sequences
let fibonacci = lazy {
fn fib_sequence() -> Iterator<Int> {
let (a, b) = (0, 1)
loop {
yield a
(a, b) = (b, a + b)
}
}
fib_sequence()
}
// Take first 10 fibonacci numbers
let first_ten = fibonacci.take(10).collect()
// Lazy evaluation with generators
fn range(start: Int, end: Int) -> Iterator<Int> {
lazy {
var current = start
while current < end {
yield current
current += 1
}
}
}
```
### Currying and Partial Application
```flex
// Curried functions
fn add(a: Int) -> (Int) -> Int {
|b| a + b
}
let add_five = add(5)
let result = add_five(3) // 8
// Partial application
fn multiply(a: Int, b: Int, c: Int) -> Int {
a * b * c
}
let multiply_by_2_and_3 = multiply(2, 3, _) // Partial application
let result = multiply_by_2_and_3(4) // 24
```
---
## Generic Programming
### Generic Functions
```flex
// Basic generic function
fn identity<T>(value: T) -> T {
value
}
let number = identity(42)
let text = identity("hello")
// Multiple type parameters
fn pair<T, U>(first: T, second: U) -> (T, U) {
(first, second)
}
let result = pair("hello", 42) // (String, Int)
// Generic with constraints
fn compare<T>(a: T, b: T) -> Bool
where T: Comparable {
a < b
}
```
### Generic Types
```flex
// Generic struct
struct Container<T> {
value: T
}
impl<T> Container<T> {
fn new(value: T) -> Container<T> {
Container { value }
}
fn get() -> T {
self.value
}
fn map<U>(f: T -> U) -> Container<U> {
Container { value: f(self.value) }
}
}
let int_container = Container.new(42)
let string_container = int_container.map(|x| x.to_string())
```
### Type Constraints and Bounds
```flex
// Trait bounds
trait Serializable {
fn serialize() -> String
}
trait Deserializable {
fn deserialize(data: String) -> Self
}
fn save_and_load<T>(item: T) -> T
where T: Serializable + Deserializable {
let serialized = item.serialize()
T.deserialize(serialized)
}
// Associated types
trait Iterator {
type Item
fn next() -> Optional<Self.Item>
}
trait Collect<T> {
fn collect<I>(iter: I) -> Self
where I: Iterator<Item = T>
}
```
### Generic Enums
```flex
// Generic Result type
enum Result<T, E> {
Ok(T),
Err(E)
}
impl<T, E> Result<T, E> {
fn is_ok() -> Bool {
match self {
Ok(_) => true,
Err(_) => false
}
}
fn map<U>(f: T -> U) -> Result<U, E> {
match self {
Ok(value) => Ok(f(value)),
Err(error) => Err(error)
}
}
}
// Generic tree structure
enum Tree<T> {
Leaf(T),
Branch(Box<Tree<T>>, Box<Tree<T>>)
}
```
---
## Metaprogramming
### Macros
```flex
// Simple macro
macro debug_print(expr) {
println("Debug: {} = {}", stringify!(expr), expr)
}
debug_print!(x + y) // Expands to: println("Debug: x + y = {}", x + y)
// Macro with multiple patterns
macro vec![
() => { Vec.new() },
($elem:expr; $n:expr) => { Vec.with_capacity($n).fill($elem) },
($($x:expr),+ $(,)?) => { Vec.from([$($x),+]) }
]
let v1 = vec![]
let v2 = vec![0; 10]
let v3 = vec![1, 2, 3, 4]
```
### Compile-time Code Generation
```flex
// Derive macro for automatic trait implementation
@derive(Debug, Clone, PartialEq)
struct Point {
x: Float,
y: Float
}
// Custom derive macro
@derive(Serialize, Deserialize)
struct User {
name: String,
age: Int,
email: String
}
// Procedural macro for generating code
@generate_builder
struct Config {
host: String,
port: Int,
ssl: Bool
}
// Generated builder pattern:
let config = Config.builder()
.host("localhost")
.port(8080)
.ssl(true)
.build()
```
### Reflection and Introspection
```flex
// Type information at runtime
fn print_type_info<T>() {
let type_info = TypeInfo.of::<T>()
println("Type name: {}", type_info.name())
println("Size: {} bytes", type_info.size())
println("Alignment: {}", type_info.alignment())
}
// Runtime reflection
struct Person {
name: String,
age: Int
}
let person = Person { name: "Alice", age: 25 }
let type_info = person.type_info()
for field in type_info.fields() {
let value = person.get_field(field.name())
println("{}: {}", field.name(), value)
}
```
### Template Metaprogramming
```flex
// Compile-time computation
const fn factorial(n: Int) -> Int {
if n <= 1 { 1 } else { n * factorial(n - 1) }
}
const FACT_10 = factorial(10) // Computed at compile time
// Template specialization
template<T>
struct Serializer {
fn serialize(value: T) -> String {
// Generic implementation
value.to_string()
}
}
// Specialization for specific types
template<>
struct Serializer<String> {
fn serialize(value: String) -> String {
"\"{value}\""
}
}
```
---
## Concurrency and Parallelism
### Async/Await
```flex
// Basic async function
async fn fetch_data(url: String) -> Result<String, Error> {
let response = http.get(url).await?
let body = response.text().await?
Ok(body)
}
// Using async functions
async fn main() {
let result = fetch_data("https://api.example.com/data").await
match result {
Ok(data) => println("Received: {data}"),
Err(error) => println("Error: {error}")
}
}
// Concurrent execution
async fn fetch_multiple() {
let futures = [
fetch_data("https://api1.example.com"),
fetch_data("https://api2.example.com"),
fetch_data("https://api3.example.com")
]
let results = futures.join().await
for result in results {
println("Result: {:?}", result)
}
}
```
### Channels and Message Passing
```flex
use std.sync.{Channel, Sender, Receiver}
// Creating channels
let (sender, receiver) = Channel.new::<String>()
// Producer task
async fn producer(sender: Sender<String>) {
for i in 0..10 {
sender.send("Message {i}").await
}
sender.close()
}
// Consumer task
async fn consumer(receiver: Receiver<String>) {
while let Some(message) = receiver.recv().await {
println("Received: {message}")
}
}
// Running tasks
async fn main() {
let (tx, rx) = Channel.new()
spawn(producer(tx))
spawn(consumer(rx))
// Wait for completion
sleep(Duration.seconds(1)).await
}
```
### Parallel Processing
```flex
use std.parallel.{par_iter, par_map, par_reduce}
// Parallel iteration
let numbers = (0..1_000_000).collect()
let sum = numbers.par_iter()
.map(|x| x * x)
.reduce(0, |acc, x| acc + x)
// Parallel map
let results = numbers.par_map(|x| expensive_computation(x))
// Work stealing
async fn parallel_work() {
let tasks = (0..100).map(|i| {
spawn(async move {
// Some work
compute_something(i).await
})
}).collect()
let results = tasks.join_all().await
}
```
### Actors and Supervision
```flex
use std.actor.{Actor, ActorRef, ActorSystem}
// Actor definition
struct CounterActor {
count: Int
}
enum CounterMessage {
Increment,
Decrement,
GetCount(Sender<Int>)
}
impl Actor for CounterActor {
type Message = CounterMessage
async fn handle(&mut self, message: CounterMessage) {
match message {
Increment => self.count += 1,
Decrement => self.count -= 1,
GetCount(reply_to) => {
reply_to.send(self.count).await
}
}
}
}
// Using actors
async fn main() {
let system = ActorSystem.new()
let counter = system.spawn(CounterActor { count: 0 })
counter.send(Increment).await
counter.send(Increment).await
let (tx, rx) = Channel.new()
counter.send(GetCount(tx)).await
let count = rx.recv().await // 2
}
```
### Synchronization Primitives
```flex
use std.sync.{Mutex, RwLock, Semaphore, Barrier}
// Mutex for exclusive access
let shared_data = Mutex.new(0)
async fn increment_shared() {
let mut guard = shared_data.lock().await
*guard += 1
}
// RwLock for reader-writer access
let shared_map = RwLock.new(HashMap.new())
async fn read_data(key: String) -> Optional<String> {
let guard = shared_map.read().await
guard.get(key).cloned()
}
async fn write_data(key: String, value: String) {
let mut guard = shared_map.write().await
guard.insert(key, value)
}
// Semaphore for limiting concurrency
let semaphore = Semaphore.new(3) // Max 3 concurrent operations
async fn limited_operation() {
let _permit = semaphore.acquire().await
// Only 3 of these can run concurrently
expensive_operation().await
}
```
---
## Module System
### Basic Modules
```flex
// math.flex
module math {
// Public exports
export fn add(a: Int, b: Int) -> Int {
a + b
}
export fn multiply(a: Int, b: Int) -> Int {
a * b
}
export const PI = 3.14159
// Private function
fn internal_helper() -> Int {
42
}
}
// main.flex
import math
// or
import math.{add, PI}
// or
import math.*
fn main() {
let result = math.add(5, 3)
println("Result: {result}")
println("PI: {math.PI}")
}
```
### Nested Modules
```flex
// utils/string.flex
module utils.string {
export fn capitalize(s: String) -> String {
if s.is_empty() {
return s
}
s.chars().first().to_uppercase() + s.slice(1..)
}
export fn reverse(s: String) -> String {
s.chars().reverse().collect()
}
}
// utils/math.flex
module utils.math {
export fn gcd(a: Int, b: Int) -> Int {
if b == 0 { a } else { gcd(b, a % b) }
}
}
// main.flex
import utils.string.capitalize
import utils.math
fn main() {
let text = capitalize("hello")
let result = utils.math.gcd(48, 18)
}
```
### Module Aliases and Re-exports
```flex
// Create alias for long module names
import very.long.module.name as short
// Re-export from other modules
module my_utils {
// Re-export everything from string utils
export use utils.string.*
// Re-export specific items
export use utils.math.gcd
// Add our own functions
export fn my_function() -> String {
"Hello from my_utils"
}
}
```
### Conditional Compilation
```flex
module platform_specific {
#[cfg(target_os = "windows")]
export fn get_path_separator() -> String {
"\\"
}
#[cfg(target_os = "unix")]
export fn get_path_separator() -> String {
"/"
}
#[cfg(feature = "advanced")]
export fn advanced_feature() {
// Only included if "advanced" feature is enabled
}
}
```
---
## Kernel Extensions
### Using Existing Kernels
```flex
// Import kernels
use kernel AIKernel
use kernel WebKernel
use kernel SystemKernel
// AI functionality becomes available
let model = LLM.load("gpt-4")
let response = model.generate("Hello, world!")
// Web functionality
@api("/users")
service UserService {
@get("/{id}")
fn get_user(id: String) -> User { }
}
// System functionality
unsafe {
let ptr = malloc(1024)
free(ptr)
}
```
### Creating Custom Kernels
```flex
// database_kernel.flex
kernel DatabaseKernel {
// Define new syntax
syntax {
// SQL query blocks
query_block: "query" "{" sql_statement "}"
// Table definitions
table_def: "table" identifier "{" field_list "}"
}
// Syntax transformation
impl {
fn transform_query_block(ast: QueryBlock) -> Expression {
let sql = ast.sql_statement.to_string()
return call_expression("execute_sql", [string_literal(sql)])
}
fn transform_table_def(ast: TableDef) -> Expression {
// Generate struct definition from table schema
generate_struct(ast.identifier, ast.field_list)
}
}
// Kernel exports (available when kernel is imported)
export {
trait Database {
fn connect(url: String) -> Self
fn execute(query: String) -> Result<ResultSet, Error>
fn transaction<T>(f: () -> T) -> Result<T, Error>
}
struct ResultSet {
rows: List<Row>
}
fn connect_postgres(url: String) -> impl Database { }
fn connect_mysql(url: String) -> impl Database { }
}
// Kernel dependencies
dependencies {
std.collections
std.io
external.libpq // External C library
}
}
```
### Advanced Kernel Features
```flex
// ml_kernel.flex
kernel MLKernel {
// Type-level programming for tensor shapes
syntax {
tensor_type: "Tensor" "<" shape_spec "," dtype ">"
shape_spec: "[" dimension_list "]"
}
// Compile-time shape checking
impl {
fn check_tensor_operations(ast: BinaryOp) -> Result<(), Error> {
match ast.operator {
MatMul => {
let left_shape = ast.left.get_tensor_shape()
let right_shape = ast.right.get_tensor_shape()
if !shapes_compatible_for_matmul(left_shape, right_shape) {
return Err("Incompatible tensor shapes for matrix multiplication")
}
}
_ => {}
}
Ok(())
}
}
export {
struct Tensor<Shape, DType> {
data: Array<DType>
}
// Automatic differentiation
trait Differentiable {
fn backward(gradient: Self) -> Self
}
// Neural network layers
struct Linear<InputSize, OutputSize> {
weights: Tensor<[InputSize, OutputSize], Float32>,
bias: Tensor<[OutputSize], Float32>
}
impl<I, O> Linear<I, O> {
fn forward(input: Tensor<[BatchSize, I], Float32>)
-> Tensor<[BatchSize, O], Float32> {
input @ self.weights + self.bias
}
}
}
}
// Using the ML kernel
use kernel MLKernel
fn main() {
// Type-safe tensor operations
let x: Tensor<[32, 784], Float32> = load_batch()
let layer = Linear::<784, 128>::new()
let output = layer.forward(x) // Tensor<[32, 128], Float32>
// Compile-time shape checking prevents errors
// let invalid = x @ output // Compilation error: incompatible shapes
}
```
---
## AI and GenAI Integration
### LLM Integration
```flex
use kernel AIKernel
// Basic LLM usage
async fn basic_llm_example() {
let model = LLM.load("gpt-4") {
api_key: env("OPENAI_API_KEY"),
max_tokens: 1000,
temperature: 0.7
}
let response = model.generate("Explain quantum computing").await?
println("Response: {response}")
}
// Structured generation
struct CodeReview {
summary: String,
issues: List<String>,
suggestions: List<String>,
rating: Int // 1-10
}
async fn code_review_example() {
let model = LLM.load("gpt-4")
let code = read_file("src/main.flex")?
let prompt = "Review this code and provide structured feedback: {code}"
let review: CodeReview = model.generate_structured(prompt).await?
println("Summary: {review.summary}")
println("Rating: {review.rating}/10")
for issue in review.issues {
println("Issue: {issue}")
}
}
```
### Embeddings and Vector Operations
```flex
// Text embeddings
async fn embedding_example() {
let embedder = Embedder.load("text-embedding-ada-002")
let texts = [
"The cat sat on the mat",
"A feline rested on the rug",
"The dog ran in the park"
]
let embeddings = embedder.embed_batch(texts).await?
// Compute similarity
let similarity = cosine_similarity(embeddings[0], embeddings[1])
println("Similarity: {similarity}")
}
// Vector database integration
async fn vector_search_example() {
let db = VectorDB.connect("pinecone://...")
// Index documents
let documents = load_documents("docs/")
for doc in documents {
let embedding = embedder.embed(doc.content).await?
db.upsert(doc.id, embedding, doc.metadata).await?
}
// Search
let query = "How to implement async functions?"
let query_embedding = embedder.embed(query).await?
let results = db.search(query_embedding, top_k: 5).await?
for result in results {
println("Document: {result.id}, Score: {result.score}")
}
}
```
### Fine-tuning and Training
```flex
// Fine-tuning example
async fn fine_tune_model() {
let base_model = LLM.load("gpt-3.5-turbo")
let training_data = load_training_data("training.jsonl")
let validation_data = load_training_data("validation.jsonl")
let fine_tuned = base_model.fine_tune() {
training_data,
validation_data,
epochs: 3,
learning_rate: 0.0001,
batch_size: 16
}.await?
fine_tuned.save("models/my_fine_tuned_model")?
}
// Custom training loop
async fn custom_training() {
let model = TransformerModel.new() {
vocab_size: 50000,
hidden_size: 768,
num_layers: 12,
num_heads: 12
}
let optimizer = AdamW.new(model.parameters()) {
learning_rate: 0.0001,
weight_decay: 0.01
}
for epoch in 0..num_epochs {
for batch in training_loader {
let logits = model.forward(batch.input_ids)
let loss = cross_entropy_loss(logits, batch.labels)
optimizer.zero_grad()
loss.backward()
optimizer.step()
if step % 100 == 0 {
println("Epoch {epoch}, Step {step}, Loss: {loss}")
}
}
}
}
```
### Multimodal AI
```flex
// Vision-Language models
async fn multimodal_example() {
let model = VisionLanguageModel.load("gpt-4-vision")
let image = Image.load("photo.jpg")?
let prompt = "Describe what you see in this image"
let response = model.generate(prompt, image).await?
println("Description: {response}")
}
// Audio processing
async fn audio_example() {
let whisper = SpeechToText.load("whisper-large")
let tts = TextToSpeech.load("eleven-labs")
// Speech to text
let audio = Audio.load("recording.wav")?
let transcript = whisper.transcribe(audio).await?
// Text to speech
let speech = tts.synthesize("Hello, this is generated speech").await?
speech.save("output.wav")?
}
```
### AI Agents and Workflows
```flex
// AI Agent framework
struct ResearchAgent {
llm: LLM,
search_tool: SearchTool,
memory: ConversationMemory
}
impl ResearchAgent {
async fn research_topic(topic: String) -> String {
let search_results = self.search_tool.search(topic).await?
let context = search_results.iter()
.take(5)
.map(|r| r.content)
.join("\n\n")
let prompt = """
Based on the following search results, provide a comprehensive summary of {topic}:
{context}
Please provide a well-structured response with key points and conclusions.
"""
let response = self.llm.generate(prompt).await?
self.memory.add_interaction(topic, response.clone())
response
}
}
// Multi-agent collaboration
async fn multi_agent_example() {
let researcher = ResearchAgent.new()
let writer = WritingAgent.new()
let reviewer = ReviewAgent.new()
// Research phase
let research = researcher.research_topic("Quantum Computing").await?
// Writing phase
let article = writer.write_article(research).await?
// Review phase
let review = reviewer.review_content(article).await?
let final_article = writer.revise_article(article, review).await?
println("Final article: {final_article}")
}
```
---
## API Development
### HTTP Server and Routing
```flex
use kernel WebKernel
// Basic HTTP server
@api
struct UserAPI {
db: Database
}
impl UserAPI {
@get("/users")
async fn list_users(
query: Query<UserFilter>,
pagination: Pagination
) -> Result<Json<List<User>>, Error> {
let users = self.db.find_users(query.filter, pagination).await?
Ok(Json(users))
}
@get("/users/{id}")
async fn get_user(
path: Path<UserId>
) -> Result<Json<User>, Error> {
let user = self.db.find_user(path.id).await?
.ok_or(Error.NotFound("User not found"))?
Ok(Json(user))
}
@post("/users")
async fn create_user(
body: Json<CreateUserRequest>
) -> Result<Json<User>, Error> {
let user = self.db.create_user(body.into_inner()).await?
Ok(Json(user))
}
@put("/users/{id}")
async fn update_user(
path: Path<UserId>,
body: Json<UpdateUserRequest>
) -> Result<Json<User>, Error> {
let user = self.db.update_user(path.id, body.into_inner()).await?
Ok(Json(user))
}
@delete("/users/{id}")
async fn delete_user(
path: Path<UserId>
) -> Result<StatusCode, Error> {
self.db.delete_user(path.id).await?
Ok(StatusCode.NO_CONTENT)
}
}
// Server setup
async fn main() {
let db = Database.connect("postgresql://localhost/myapp").await?
let api = UserAPI { db }
let server = HttpServer.new()
.bind("127.0.0.1:8080")?
.service(api)
.middleware(LoggingMiddleware.new())
.middleware(CorsMiddleware.permissive())
.run()
.await?
}
```
### Middleware and Authentication
```flex
// Custom middleware
struct AuthMiddleware {
secret_key: String
}
impl Middleware for AuthMiddleware {
async fn call(
req: Request,
next: Next
) -> Result<Response, Error> {
let token = req.headers()
.get("Authorization")
.and_then(|h| h.strip_prefix("Bearer "))
.ok_or(Error.Unauthorized("Missing token"))?
let claims = verify_jwt(token, &self.secret_key)?
req.extensions_mut().insert(claims)
next.call(req).await
}
}
// Protected endpoints
@api
struct ProtectedAPI {
@get("/profile")
@middleware(AuthMiddleware)
async fn get_profile(
claims: Extension<JwtClaims>
) -> Result<Json<UserProfile>, Error> {
let profile = get_user_profile(claims.user_id).await?
Ok(Json(profile))
}
}
```
### WebSocket Support
```flex
// WebSocket handler
@websocket("/chat")
async fn chat_handler(
socket: WebSocket,
state: State<ChatState>
) -> Result<(), Error> {
let (sender, mut receiver) = socket.split()
// Handle incoming messages
while let Some(message) = receiver.next().await {
match message? {
Message.Text(text) => {
let chat_message = ChatMessage {
user: "anonymous",
content: text,
timestamp: now()
}
// Broadcast to all connected clients
state.broadcast(chat_message).await?
}
Message.Close(_) => break,
_ => {}
}
}
Ok(())
}
// WebSocket state management
struct ChatState {
clients: Arc<Mutex<HashMap<String, WebSocketSender>>>
}
impl ChatState {
async fn broadcast(message: ChatMessage) -> Result<(), Error> {
let clients = self.clients.lock().await
let json_message = serde_json.to_string(&message)?
for (_, sender) in clients.iter() {
sender.send(Message.Text(json_message.clone())).await?
}
Ok(())
}
}
```
### GraphQL Integration
```flex
// GraphQL schema definition
@graphql_object
struct User {
id: ID,
name: String,
email: String,
posts: List<Post>
}
@graphql_object
struct Post {
id: ID,
title: String,
content: String,
author: User
}
// GraphQL resolvers
struct Query;
@graphql_object
impl Query {
async fn user(id: ID) -> Result<Optional<User>, Error> {
database.find_user(id).await
}
async fn users(
first: Optional<Int>,
after: Optional<String>
) -> Result<Connection<User>, Error> {
database.find_users_paginated(first, after).await
}
async fn posts(
filter: Optional<PostFilter>
) -> Result<List<Post>, Error> {
database.find_posts(filter).await
}
}
struct Mutation;
@graphql_object
impl Mutation {
async fn create_user(
input: CreateUserInput
) -> Result<User, Error> {
database.create_user(input).await
}
async fn create_post(
input: CreatePostInput
) -> Result<Post, Error> {
database.create_post(input).await
}
}
// GraphQL server
async fn main() {
let schema = Schema.build(Query, Mutation, EmptySubscription)
.data(database)
.finish()
let server = HttpServer.new()
.route("/graphql", GraphQLHandler.new(schema))
.route("/graphiql", GraphiQLHandler.new("/graphql"))
.run()
.await?
}
```
### API Documentation and OpenAPI
```flex
// Automatic OpenAPI generation
@api
@openapi(
title: "User Management API",
version: "1.0.0",
description: "API for managing users and their data"
)
struct UserAPI {
@get("/users")
@openapi(
summary: "List all users",
description: "Retrieve a paginated list of users",
responses: {
200: "List of users",
400: "Invalid parameters"
}
)
async fn list_users(
@openapi(description: "Filter criteria")
query: Query<UserFilter>,
@openapi(description: "Pagination parameters")
pagination: Pagination
) -> Result<Json<List<User>>, Error> {
// Implementation
}
}
// Generate OpenAPI spec
fn main() {
let spec = UserAPI.generate_openapi_spec()
write_file("openapi.json", spec.to_json())?
// Start server with documentation
let server = HttpServer.new()
.service(UserAPI.new())
.route("/docs", SwaggerUIHandler.new("/openapi.json"))
.route("/openapi.json", JsonHandler.new(spec))
.run()
.await?
}
```
---
## System Programming
### Memory Management
```flex
use kernel SystemKernel
// Manual memory management
unsafe {
// Allocate raw memory
let ptr: *mut u8 = malloc(1024)
// Check for allocation failure
if ptr.is_null() {
panic("Memory allocation failed")
}
// Use the memory
for i in 0..1024 {
*ptr.offset(i) = i as u8
}
// Free the memory
free(ptr)
}
// Stack allocation for performance-critical code
fn fast_computation() {
// Allocate on stack
let buffer: [u8; 4096] = [0; 4096]
// Use buffer for computation
for i in 0..buffer.len() {
buffer[i] = compute_value(i)
}
}
// Custom allocators
struct PoolAllocator {
pool: *mut u8,
size: usize,
used: usize
}
impl PoolAllocator {
fn new(size: usize) -> Self {
unsafe {
let pool = malloc(size)
PoolAllocator { pool, size, used: 0 }
}
}
fn allocate(size: usize) -> Optional<*mut u8> {
if self.used + size > self.size {
return None
}
unsafe {
let ptr = self.pool.offset(self.used as isize)
self.used += size
Some(ptr)
}
}
}
```
### Low-level Operations
```flex
// Bit manipulation
fn bit_operations() {
let mut value: u32 = 0b1010_1100
// Set bit
value |= 1 << 3
// Clear bit
value &= !(1 << 2)
// Toggle bit
value ^= 1 << 1
// Check bit
let is_set = (value & (1 << 4)) != 0
// Count set bits
let count = value.count_ones()
// Find first set bit
let first = value.trailing_zeros()
}
// Inline assembly
fn assembly_example() {
let result: u64
unsafe {
asm!(
"mov {}, 42",
out(reg) result,
options(pure, nomem, nostack)
)
}
println("Result from assembly: {result}")
}
// SIMD operations
fn simd_example() {
use std.simd.{f32x4, u32x4}
let a = f32x4::new(1.0, 2.0, 3.0, 4.0)
let b = f32x4::new(5.0, 6.0, 7.0, 8.0)
let sum = a + b // Vectorized addition
let product = a * b // Vectorized multiplication
println("SIMD sum: {:?}", sum.to_array())
}
```
### FFI (Foreign Function Interface)
```flex
// C library bindings
extern "C" {
fn strlen(s: *const c_char) -> c_size_t
fn malloc(size: c_size_t) -> *mut c_void
fn free(ptr: *mut c_void)
fn printf(format: *const c_char, ...) -> c_int
}
// Safe wrapper for C functions
fn safe_strlen(s: &str) -> usize {
let c_str = CString.new(s).unwrap()
unsafe {
strlen(c_str.as_ptr()) as usize
}
}
// Calling C++ code
extern "C++" {
type CppClass
fn create_cpp_object() -> *mut CppClass
fn cpp_method(obj: *mut CppClass, value: i32) -> i32
fn destroy_cpp_object(obj: *mut CppClass)
}
// RAII wrapper for C++ objects
struct CppWrapper {
ptr: *mut CppClass
}
impl CppWrapper {
fn new() -> Self {
unsafe {
CppWrapper {
ptr: create_cpp_object()
}
}
}
fn call_method(value: i32) -> i32 {
unsafe {
cpp_method(self.ptr, value)
}
}
}
impl Drop for CppWrapper {
fn drop() {
unsafe {
destroy_cpp_object(self.ptr)
}
}
}
```
### Hardware Interfaces
```flex
// Memory-mapped I/O
struct MemoryMappedRegister {
address: *mut u32
}
impl MemoryMappedRegister {
fn new(address: usize) -> Self {
MemoryMappedRegister {
address: address as *mut u32
}
}
fn read() -> u32 {
unsafe {
std.ptr.read_volatile(self.address)
}
}
fn write(value: u32) {
unsafe {
std.ptr.write_volatile(self.address, value)
}
}
}
// Interrupt handling
@interrupt_handler
fn timer_interrupt() {
// Handle timer interrupt
println("Timer interrupt occurred")
// Clear interrupt flag
let timer_control = MemoryMappedRegister.new(0x4000_0000)
timer_control.write(timer_control.read() | 0x01)
}
// DMA operations
struct DMAController {
base_address: *mut u8
}
impl DMAController {
fn transfer(
source: *const u8,
dest: *mut u8,
size: usize
) {
unsafe {
// Configure DMA transfer
let src_reg = self.base_address.offset(0x00) as *mut u32
let dst_reg = self.base_address.offset(0x04) as *mut u32
let size_reg = self.base_address.offset(0x08) as *mut u32
let ctrl_reg = self.base_address.offset(0x0C) as *mut u32
std.ptr.write_volatile(src_reg, source as u32)
std.ptr.write_volatile(dst_reg, dest as u32)
std.ptr.write_volatile(size_reg, size as u32)
std.ptr.write_volatile(ctrl_reg, 0x01) // Start transfer
// Wait for completion
while (std.ptr.read_volatile(ctrl_reg) & 0x02) == 0 {
// Busy wait
}
}
}
}
```
---
## Error Handling
### Result Type and Error Propagation
```flex
// Basic Result usage
enum Result<T, E> {
Ok(T),
Err(E)
}
fn divide(a: Float, b: Float) -> Result<Float, String> {
if b == 0.0 {
Err("Division by zero")
} else {
Ok(a / b)
}
}
// Error propagation with ?
fn complex_calculation() -> Result<Float, String> {
let a = divide(10.0, 2.0)? // Propagates error if any
let b = divide(a, 3.0)?
let c = divide(b, 4.0)?
Ok(c)
}
// Multiple error types
enum MathError {
DivisionByZero,
Overflow,
InvalidInput
}
enum IoError {
FileNotFound,
PermissionDenied,
NetworkError
}
// Combined error type
enum AppError {
Math(MathError),
Io(IoError),
Other(String)
}
impl From<MathError> for AppError {
fn from(err: MathError) -> AppError {
AppError.Math(err)
}
}
impl From<IoError> for AppError {
fn from(err: IoError) -> AppError {
AppError.Io(err)
}
}
```
### Exception Handling
```flex
// Try-catch for exceptions
fn risky_operation() {
try {
let file = File.open("nonexistent.txt")?
let content = file.read_to_string()?
process_content(content)
} catch FileNotFoundError as e {
println("File not found: {e.message}")
} catch PermissionError as e {
println("Permission denied: {e.message}")
} catch error {
println("Unexpected error: {error}")
} finally {
cleanup_resources()
}
}
// Custom exceptions
exception ValidationError {
field: String,
message: String
}
fn validate_user(user: User) -> Result<(), ValidationError> {
if user.name.is_empty() {
throw ValidationError {
field: "name",
message: "Name cannot be empty"
}
}
if user.age < 0 {
throw ValidationError {
field: "age",
message: "Age cannot be negative"
}
}
Ok(())
}
```
### Error Recovery and Retry
```flex
// Retry mechanism
async fn retry_operation<T, E>(
operation: async || -> Result<T, E>,
max_attempts: Int,
delay: Duration
) -> Result<T, E> {
let mut attempts = 0
loop {
match operation().await {
Ok(result) => return Ok(result),
Err(error) => {
attempts += 1
if attempts >= max_attempts {
return Err(error)
}
sleep(delay).await
delay *= 2 // Exponential backoff
}
}
}
}
// Circuit breaker pattern
struct CircuitBreaker {
failure_count: Int,
failure_threshold: Int,
timeout: Duration,
last_failure_time: Optional<Instant>
}
impl CircuitBreaker {
async fn call<T, E>(
operation: async || -> Result<T, E>
) -> Result<T, E> {
if self.is_open() {
return Err("Circuit breaker is open")
}
match operation().await {
Ok(result) => {
self.reset()
Ok(result)
}
Err(error) => {
self.record_failure()
Err(error)
}
}
}
fn is_open() -> Bool {
self.failure_count >= self.failure_threshold &&
self.last_failure_time
.map(|time| time.elapsed() < self.timeout)
.unwrap_or(false)
}
}
```
### Panic Handling
```flex
// Panic with custom message
fn critical_check(value: Int) {
if value < 0 {
panic("Value must be non-negative, got: {value}")
}
}
// Panic hook for custom handling
fn setup_panic_handler() {
std.panic.set_hook(|panic_info| {
let location = panic_info.location()
.map(|loc| format!("{}:{}:{}", loc.file(), loc.line(), loc.column()))
.unwrap_or("unknown location".to_string())
let message = panic_info.payload()
.downcast_ref::<&str>()
.unwrap_or(&"unknown panic")
eprintln("PANIC at {location}: {message}")
// Log to file, send to monitoring service, etc.
log_panic(location, message)
})
}
// Catching panics
fn safe_operation() -> Result<String, String> {
std.panic.catch_unwind(|| {
risky_function_that_might_panic()
}).map_err(|_| "Function panicked".to_string())
}
```
---
## Standard Library
### Collections
```flex
use std.collections.*
// Vector (dynamic array)
let mut vec = Vec.new()
vec.push(1)
vec.push(2)
vec.push(3)
let vec2 = vec![1, 2, 3, 4, 5]
let sliced = vec2.slice(1..4) // [2, 3, 4]
// HashMap
let mut map = HashMap.new()
map.insert("key1", "value1")
map.insert("key2", "value2")
let map2 = hashmap! {
"name" => "Alice",
"age" => "25"
}
// HashSet
let set1 = hashset![1, 2, 3, 4]
let set2 = hashset![3, 4, 5, 6]
let intersection = set1.intersection(&set2) // {3, 4}
// BTreeMap (ordered map)
let mut btree = BTreeMap.new()
btree.insert(3, "three")
btree.insert(1, "one")
btree.insert(2, "two")
// Iteration is in sorted order
// Deque (double-ended queue)
let mut deque = VecDeque.new()
deque.push_front(1)
deque.push_back(2)
deque.push_front(0) // [0, 1, 2]
// Priority queue
let mut pq = BinaryHeap.new()
pq.push(3)
pq.push(1)
pq.push(4)
let max = pq.pop() // Some(4)
```
### Iterators and Functional Operations
```flex
use std.iter.*
let numbers = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
// Basic iterator operations
let result = numbers.iter()
.filter(|&x| x % 2 == 0) // Even numbers
.map(|&x| x * x) // Square them
.collect::<Vec<_>>() // [4, 16, 36, 64, 100]
// Reduce operations
let sum = numbers.iter().sum()
let product = numbers.iter().product()
let max = numbers.iter().max()
let min = numbers.iter().min()
// Advanced operations
let grouped = numbers.iter()
.group_by(|&x| x % 3)
.collect::<HashMap<_, Vec<_>>>()
let windowed = numbers.iter()
.windows(3)
.map(|window| window.iter().sum())
.collect::<Vec<_>>()
// Lazy evaluation
let fibonacci = (0..)
.scan((0, 1), |state, _| {
let next = state.0 + state.1
*state = (state.1, next)
Some(state.0)
})
.take(10)
.collect::<Vec<_>>()
// Parallel iteration
use std.parallel.*
let parallel_sum = numbers.par_iter()
.map(|&x| expensive_computation(x))
.sum()
```
### String Processing
```flex
use std.string.*
// String creation and manipulation
let s1 = "Hello, World!"
let s2 = String.from("Hello")
let s3 = format!("Number: {}", 42)
// String operations
let uppercase = s1.to_uppercase()
let lowercase = s1.to_lowercase()
let trimmed = " hello ".trim()
let replaced = s1.replace("World", "Flex")
// String splitting and joining
let parts = "a,b,c,d".split(',').collect::<Vec<_>>()
let joined = parts.join(" | ")
// Pattern matching
if s1.starts_with("Hello") {
println("Greeting detected")
}
let contains_world = s1.contains("World")
let position = s1.find("World") // Some(7)
// Regular expressions
use std.regex.Regex
let re = Regex.new(r"\d+").unwrap()
let numbers = re.find_all("abc 123 def 456 ghi")
.map(|m| m.as_str().parse::<i32>().unwrap())
.collect::<Vec<_>>() // [123, 456]
// String interpolation
let name = "Alice"
let age = 25
let message = "Hello, {name}! You are {age} years old."
```
### File I/O and Networking
```flex
use std.fs.*
use std.io.*
use std.net.*
// File operations
let content = read_to_string("file.txt")?
write("output.txt", "Hello, World!")?
let mut file = File.open("data.txt")?
let mut buffer = String.new()
file.read_to_string(&mut buffer)?
// Directory operations
let entries = read_dir(".")?
.filter_map(|entry| entry.ok())
.filter(|entry| entry.path().is_file())
.collect::<Vec<_>>()
create_dir_all("path/to/nested/directory")?
remove_file("unwanted.txt")?
// HTTP client
use std.http.*
let client = HttpClient.new()
let response = client.get("https://api.example.com/data").await?
let json: serde_json.Value = response.json().await?
let post_response = client.post("https://api.example.com/users")
.json(&user_data)
.send()
.await?
// TCP networking
let listener = TcpListener.bind("127.0.0.1:8080").await?
while let Ok((stream, addr)) = listener.accept().await {
spawn(async move {
handle_client(stream, addr).await
})
}
async fn handle_client(mut stream: TcpStream, addr: SocketAddr) {
let mut buffer = [0; 1024]
while let Ok(n) = stream.read(&mut buffer).await {
if n == 0 { break }
let request = String.from_utf8_lossy(&buffer[..n])
let response = process_request(request)
stream.write_all(response.as_bytes()).await?
}
}
```
### Date and Time
```flex
use std.time.*
// Current time
let now = Instant.now()
let system_time = SystemTime.now()
// Duration
let duration = Duration.from_secs(60)
let later = now + duration
// Date and time formatting
use std.chrono.*
let dt = DateTime.now()
let formatted = dt.format("%Y-%m-%d %H:%M:%S")
let parsed = DateTime.parse("2023-12-25 15:30:00", "%Y-%m-%d %H:%M:%S")?
// Time zones
let utc = DateTime.now_utc()
let local = utc.to_local()
let tokyo = utc.to_timezone("Asia/Tokyo")
// Time arithmetic
let tomorrow = dt + Duration.days(1)
let last_week = dt - Duration.weeks(1)
let difference = dt2 - dt1 // Duration
```
### Serialization and Deserialization
```flex
use std.serde.*
// JSON serialization
@derive(Serialize, Deserialize)
struct Person {
name: String,
age: Int,
email: String
}
let person = Person {
name: "Alice",
age: 25,
email: "alice@example.com"
}
let json = serde_json.to_string(&person)?
let parsed: Person = serde_json.from_str(&json)?
// YAML serialization
let yaml = serde_yaml.to_string(&person)?
let parsed: Person = serde_yaml.from_str(&yaml)?
// Binary serialization
let binary = bincode.serialize(&person)?
let parsed: Person = bincode.deserialize(&binary)?
// Custom serialization
impl Serialize for CustomType {
fn serialize<S>(serializer: S) -> Result<S.Ok, S.Error>
where S: Serializer {
// Custom serialization logic
}
}
```
---
## Advanced Features
### Compile-time Computation
```flex
// Const functions
const fn factorial(n: usize) -> usize {
if n <= 1 {
1
} else {
n * factorial(n - 1)
}
}
const FACT_10: usize = factorial(10) // Computed at compile time
// Const generics
struct Array<T, const N: usize> {
data: [T; N]
}
impl<T, const N: usize> Array<T, N> {
const fn len() -> usize {
N
}
const fn is_empty() -> bool {
N == 0
}
}
// Compile-time string processing
const fn count_chars(s: &str, c: char) -> usize {
let mut count = 0
let mut chars = s.chars()
while let Some(ch) = chars.next() {
if ch == c {
count += 1
}
}
count
}
const HELLO_L_COUNT: usize = count_chars("Hello", 'l') // 2
```
### Advanced Type System
```flex
// Higher-kinded types
trait Functor<F<_>> {
fn map<A, B>(fa: F<A>, f: A -> B) -> F<B>
}
impl Functor<Optional> {
fn map<A, B>(fa: Optional<A>, f: A -> B) -> Optional<B> {
match fa {
Some(a) => Some(f(a)),
None => None
}
}
}
// Dependent types
struct Vector<T, const N: usize> {
data: [T; N]
}
fn dot_product<const N: usize>(
a: Vector<f64, N>,
b: Vector<f64, N>
) -> f64 {
let mut sum = 0.0
for i in 0..N {
sum += a.data[i] * b.data[i]
}
sum
}
// Type-level programming
trait TypeEq<T> {}
impl<T> TypeEq<T> for T {}
fn same_type<T, U>()
where T: TypeEq<U> {
// T and U are the same type
}
// Phantom types
struct PhantomData<T>
struct Meter(f64, PhantomData<Meter>)
struct Second(f64, PhantomData<Second>)
fn speed(distance: Meter, time: Second) -> MeterPerSecond {
MeterPerSecond(distance.0 / time.0)
}
```
### Memory Layout Control
```flex
// Struct layout control
@repr(C)
struct CCompatible {
a: u32,
b: u16,
c: u8
}
@repr(packed)
struct Packed {
a: u8,
b: u32 // No padding
}
@repr(align(16))
struct Aligned {
data: [u8; 12] // Aligned to 16-byte boundary
}
// Zero-cost abstractions
struct NewType(i32)
impl NewType {
fn new(value: i32) -> Self {
NewType(value)
}
fn into_inner(self) -> i32 {
self.0
}
}
// The compiler optimizes away the wrapper
let x = NewType.new(42)
let y = x.into_inner() // No runtime cost
```
### Compiler Plugins and Custom Lints
```flex
// Custom lint definition
@lint
fn check_naming_convention(item: &Item) -> LintResult {
match item {
Item.Function(func) if !func.name.is_snake_case() => {
LintResult.Warning {
message: "Function names should use snake_case",
span: func.name_span
}
}
_ => LintResult.Ok
}
}
// Compiler plugin for custom syntax
@compiler_plugin
fn matrix_literal_plugin() -> SyntaxExtension {
SyntaxExtension.new("matrix", |tokens| {
// Parse matrix literal syntax: matrix[[1, 2], [3, 4]]
// Transform to Matrix.from_rows([[1, 2], [3, 4]])
parse_matrix_literal(tokens)
})
}
// Using the custom syntax
let m = matrix[[1, 2, 3], [4, 5, 6], [7, 8, 9]]
```
### Performance Optimization
```flex
// Profile-guided optimization hints
@likely
if condition {
// This branch is likely to be taken
fast_path()
} else {
@unlikely
slow_path()
}
// Inline hints
@inline(always)
fn always_inline() {
// Always inlined
}
@inline(never)
fn never_inline() {
// Never inlined
}
// SIMD optimization
@target_feature(enable = "avx2")
fn simd_sum(data: &[f32]) -> f32 {
// Compiler can use AVX2 instructions
data.iter().sum()
}
// Memory prefetching
fn process_large_array(data: &mut [i32]) {
for i in 0..data.len() {
if i + 64 < data.len() {
prefetch(&data[i + 64]) // Prefetch future data
}
data[i] = expensive_computation(data[i])
}
}
// Branch prediction hints
fn search(arr: &[i32], target: i32) -> Option<usize> {
for (i, &value) in arr.iter().enumerate() {
if likely(value != target) {
continue
}
return Some(i)
}
None
}
```
This comprehensive developer guide covers all major features of the Flex programming language, from basic syntax to advanced system programming and AI integration. Each section builds upon previous concepts while introducing new paradigms and capabilities that make Flex a powerful and flexible language for modern software development.
