Syntax Overview

SystemScript features a C-like syntax with significant extensions for hardware manipulation, memory control, and system-level operations:

// Basic program structure
module example;

import system.io;
import system.memory;

// Constants
const MAX_BUFFER_SIZE: u32 = 4096;

// Function definition with type annotations
fn calculate_checksum(data: *u8, length: u32) -> u32 {
    let sum: u32 = 0;
    
    for (let i: u32 = 0; i < length; i++) {
        sum += *unsafe_offset(data, i);
    }
    
    return sum & 0xFFFFFFFF;
}

// Entry point
fn main() -> i32 {
    // String literals
    let message = "Hello, SystemScript!";
    io.println(message);
    
    // Direct memory allocation
    let buffer = memory.alloc<u8>(MAX_BUFFER_SIZE);
    defer memory.free(buffer);
    
    // Hardware port access
    io.port_write<u8>(0x3F8, 65);
    
    return 0;
}

Type System

SystemScript features a strong, static type system with support for low-level and high-level types:

Primitive Types

Derived Types

User-Defined Types

// Structure definition with explicit memory layout
#[repr(C, packed)]
struct NetworkPacket {
    dest_mac: [u8; 6],
    src_mac: [u8; 6],
    ethertype: u16,
    payload: [u8; 1500]
}

// Enumeration
enum ProcessState {
    Ready,
    Running,
    Blocked,
    Terminated
}

// Union for type punning
union FloatBytes {
    value: f32,
    bytes: [u8; 4]
}

// Type aliases
type byte = u8;
type size_t = u64;
type CString = *u8;

Type Safety and Unsafe Operations

SystemScript provides strong type safety by default, but allows explicit unsafe operations for low-level programming:

// Safe code by default
fn safe_example(data: &[u8]) -> u32 {
    return data.length; // Safe, bounds checked
}

// Unsafe block for low-level operations
fn unsafe_example(ptr: *u8, offset: u64) -> u8 {
    unsafe {
        let value = *memory.offset(ptr, offset);
        return value;
    }
}

Memory Model

SystemScript provides complete control over memory management with both high-level abstractions and low-level direct manipulation:

Memory Management Examples

// Manual allocation/deallocation
fn manual_memory() {
    // Allocate 1024 bytes
    let buffer = memory.alloc<u8>(1024);
    
    // Use the buffer
    buffer[0] = 42;
    
    // Explicit deallocation
    memory.free(buffer);
    
    // Scoped deallocation with defer
    let data = memory.alloc<u32>(256);
    defer memory.free(data); // Will be freed when function exits
}

// Direct memory mapping
fn map_device_memory() {
    // Map hardware device memory (GPU framebuffer)
    let framebuffer = memory.map_device(0xF0000000, 8 * 1024 * 1024);
    defer memory.unmap(framebuffer);
    
    // Write directly to mapped memory
    framebuffer[100] = 0xFF00FF00; // Set pixel color
}

Pointer Safety

// Safe pointer manipulation with bounds checking
fn safe_pointer_example() {
    let array = [1, 2, 3, 4, 5];
    let ptr = &array[0];
    
    // Bounds-checked pointer arithmetic
    let value = ptr.offset(2); // Safe access to array[2]
    
    // Null checking
    if (ptr.is_null()) {
        io.println("Null pointer detected");
    }
}

Control Flow

SystemScript provides comprehensive control flow mechanisms for precise program execution:

Basic Control Structures

// Conditionals
if (condition) {
    // code
} else if (another_condition) {
    // code
} else {
    // code
}

// Switch statement with pattern matching
switch (value) {
    case 1:
        // code
        break;
    case 2..5: // Range match
        // code
        break;
    case *: // Default case
        // code
}

// Loops
while (condition) {
    // code
}

do {
    // code
} while (condition);

for (let i = 0; i < 10; i++) {
    // code
}

// Iterator-based for loop
for (item in collection) {
    // code
}

// Infinite loop
loop {
    // code
    if (exit_condition) break;
}

Advanced Control Flow

// Early returns
fn find_value(array: &[i32], target: i32) -> bool {
    for (item in array) {
        if (item == target) return true;
    }
    return false;
}

// Named loops and breaks
outer: for (let i = 0; i < 10; i++) {
    inner: for (let j = 0; j < 10; j++) {
        if (condition) break inner;
        if (another_condition) break outer;
    }
}

// Defer statement (cleanup regardless of exit path)
fn process_file(path: str) -> Result {
    let file = fs.open(path)?;
    defer file.close();
    
    // Even if an error occurs below, file.close() will be called
    let data = file.read_all()?;
    return Ok(process_data(data));
}

// Exception handling for high-level code
try {
    let result = potentially_failing_operation();
    use_result(result);
} catch (e: IoError) {
    handle_io_error(e);
} catch (e: *) {
    handle_generic_error(e);
} finally {
    // Always executed
    cleanup();
}

fn match_example(value: any) {
    match value {
        0...9 => io.println("Single digit: {}", value),
        i32 if value > 100 => io.println("Large number: {}", value),
        "hello" | "hi" => io.println("Greeting!"),
        [i32] => io.println("Integer array with {} elements", value.length),
        Person { name, age } => io.println("Person {} is {} years old", name, age),
        _ => io.println("No match found")
    }
}

Functions & Procedures

SystemScript provides flexible function definitions with powerful features for expressive and efficient code:

Function Declarations

// Basic function
fn add(a: i32, b: i32) -> i32 {
    return a + b;
}

// Function with multiple return values
fn divide_with_remainder(a: i32, b: i32) -> (i32, i32) {
    return (a / b, a % b);
}

// Variadic functions
fn printf(format: str, args: ...any) -> i32 {
    // Implementation
}

// Generic functions
fn min<T: Comparable>(a: T, b: T) -> T {
    return if (a < b) a else b;
}

// Function with optional parameters
fn create_window(title: str, width: i32 = 800, height: i32 = 600) -> Window {
    // Implementation
}

// Function with named parameters
fn configure(name: str, options: {port: i32, timeout: i32, retries: i32}) {
    // Implementation
}

Advanced Function Features

// Function attributes
#[inline(always)]
fn performance_critical() {
    // Will be inlined at every call site
}

#[no_return]
fn fatal_error(message: str) {
    io.println("ERROR: " + message);
    system.exit(1);
}

// Calling conventions
#[calling_convention(cdecl)]
fn c_compatible_function(arg: i32) -> i32 {
    return arg * 2;
}

// Closures and lambdas
fn apply_transform(values: &[i32], transform: fn(i32) -> i32) -> [i32] {
    let result = [i32; values.length];
    for (let i = 0; i < values.length; i++) {
        result[i] = transform(values[i]);
    }
    return result;
}

// Usage with lambda
let doubled = apply_transform(numbers, |x| x * 2);

// Function overloading
fn process(value: i32) -> i32 { return value * 2; }
fn process(value: str) -> str { return value + value; }

// Higher-order functions
fn compose<A,B,C>(f: fn(B) -> C, g: fn(A) -> B) -> fn(A) -> C {
    return |x| f(g(x));
}

Modules & Libraries

SystemScript uses a robust module system for code organization and reuse:

Module System

// Defining a module
module network.protocols.http;

// Importing modules
import system.io;
import memory.{alloc, free};
import network.socket as net;

// Export declarations
pub fn parse_request(data: &[u8]) -> HttpRequest {
    // Implementation
}

// Internal (non-exported) function
fn validate_headers(headers: &[HttpHeader]) -> bool {
    // Implementation
}

// Conditional compilation
#[cfg(target_os = "linux")]
fn platform_specific() {
    // Linux-specific code
}

#[cfg(target_os = "windows")]
fn platform_specific() {
    // Windows-specific code
}

Standard Library Organization

Package Management

// Package definition (package.ss)
package {
    name: "network-protocol",
    version: "1.0.0",
    authors: ["Your Name "],
    description: "Custom network protocol implementation",
    
    dependencies: {
        "crypto": "^2.1.0",
        "socket": "^1.3.5",
        "memory-utils": {
            version: "1.0.0",
            features: ["zero-copy"]
        }
    },
    
    exports: [
        "Protocol",
        "PacketType",
        "create_packet",
        "parse_packet"
    ]
}

Direct Hardware Access

SystemScript provides direct access to hardware resources, enabling deep system control:

Port I/O

import hardware.port;

// Read from port
let value = port.read<u8>(0x3F8);

// Write to port
port.write<u8>(0x3F8, 0x41);

// Multiple port operations
unsafe {
    // Disable interrupts during port operations
    let flags = cpu.disable_interrupts();
    defer cpu.restore_interrupts(flags);
    
    // Serial port initialization sequence
    port.write<u8>(0x3F8 + 1, 0x00);    // Disable interrupts
    port.write<u8>(0x3F8 + 3, 0x80);    // Enable DLAB
    port.write<u8>(0x3F8 + 0, 0x03);    // Set divisor to 3 (38400 baud)
    port.write<u8>(0x3F8 + 1, 0x00);    // Set divisor to 3 (high byte)
    port.write<u8>(0x3F8 + 3, 0x03);    // 8 bits, no parity, 1 stop bit
    port.write<u8>(0x3F8 + 2, 0xC7);    // Enable FIFO, clear, 14-byte threshold
}

Memory-Mapped I/O

import hardware.mmio;

// Map device memory
let gpu_registers = mmio.map(0xF0000000, 4096);
defer mmio.unmap(gpu_registers);

// Register definitions
const REG_CONTROL   = 0x00;
const REG_STATUS    = 0x04;
const REG_FRAMEBUFFER_ADDR = 0x08;
const REG_WIDTH     = 0x0C;
const REG_HEIGHT    = 0x10;

// Configure device
gpu_registers[REG_WIDTH] = 1920;
gpu_registers[REG_HEIGHT] = 1080;
gpu_registers[REG_FRAMEBUFFER_ADDR] = physical_framebuffer_address;

// Enable device
gpu_registers[REG_CONTROL] = 0x01;

CPU Register Access

import hardware.cpu;

// Read CPU registers
let cr0 = cpu.read_cr0();
let eflags = cpu.read_eflags();

// Write CPU register
cpu.write_cr3(page_table_address);

// Atomic operations
let old_value = cpu.atomic_xchg(&shared_variable, new_value);

// CPU feature detection
if (cpu.has_feature(cpu.FEATURE_SSE4_2)) {
    // Use SSE 4.2 optimized code path
} else {
    // Use fallback implementation
}

Interrupt Management

import hardware.interrupts;

// Define interrupt handler
fn keyboard_handler(frame: &InterruptFrame) {
    let scancode = port.read<u8>(0x60);
    process_key(scancode);
}

// Install interrupt handler
interrupts.set_handler(0x21, keyboard_handler);

// Enable/disable interrupts
interrupts.disable();
// Critical section
interrupts.enable();

Memory Manipulation

SystemScript provides advanced memory manipulation capabilities for low-level system programming:

Direct Memory Operations

import memory;

// Raw memory operations
unsafe {
    // Set memory region to a value
    memory.set(buffer, 0, 1024);  // Zero 1024 bytes
    
    // Copy memory
    memory.copy(dest, source, 512);
    
    // Compare memory
    let equal = memory.compare(buffer1, buffer2, 256);
}

// Memory allocation with specific alignment
let aligned_buffer = memory.alloc_aligned<u8>(4096, 4096);  // Page-aligned allocation
defer memory.free_aligned(aligned_buffer);

// Memory protection
memory.protect(buffer, 4096, memory.PROT_READ | memory.PROT_WRITE);

// Non-temporal (non-cached) memory operations
memory.stream_store(large_buffer, 0, 1024 * 1024);  // Bypass cache

Virtual Memory Management

import memory.vm;

// Allocate virtual memory
let region = vm.allocate(0, 16 * 1024 * 1024);  // 16MB region
defer vm.free(region);

// Map physical memory into virtual address space
vm.map(region, physical_address, 4096, vm.MAP_READ | vm.MAP_WRITE);

// Create memory protection guard pages
vm.protect(region + 4096, 4096, vm.PROT_NONE);  // No access guard page

Memory Barriers and Caching

import memory.cache;

// Memory barriers
memory.barrier();               // Full memory barrier
memory.barrier_acquire();       // Acquire barrier
memory.barrier_release();       // Release barrier

// Cache control
cache.flush_line(address);       // Flush single cache line
cache.invalidate_line(address);  // Invalidate single cache line
cache.flush_range(addr, size);   // Flush range of addresses

import memory;
import system.io;

fn main() {
    // Allocate a buffer
    let buffer = memory.alloc<u32>(5);
    defer memory.free(buffer);
    
    // Initialize the buffer
    for (i in 0..5) {
        buffer[i] = i * 10;
    }
    
    // Print values
    for (i in 0..5) {
        io.println("buffer[{}] = {}", i, buffer[i]);
    }
}

Networking Capabilities

SystemScript provides both high-level and low-level networking capabilities:

Raw Socket Programming

import network.raw;

// Create a raw Ethernet socket
let socket = raw.create_socket("eth0");
defer socket.close();

// Define an Ethernet frame
let frame = EthernetFrame {
    dest_mac: [0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF],  // Broadcast
    src_mac: [0x00, 0x11, 0x22, 0x33, 0x44, 0x55],   // Source MAC
    ethertype: 0x0800,  // IPv4
    payload: [...]      // IP packet
};

// Send raw frame
raw.send_frame(socket, &frame);

TCP/IP Stack Access

import network.socket;
import network.ip;

// Create TCP socket
let server = socket.create(socket.AF_INET, socket.SOCK_STREAM);
defer server.close();

// Configure socket
server.set_option(socket.SO_REUSEADDR, true);

// Bind to address and port
let address = ip.Address {
    family: ip.AF_INET,
    port: 8080,
    addr: ip.parse("0.0.0.0")
};
server.bind(address);

// Listen for connections
server.listen(10);

// Accept connection
let client = server.accept();
defer client.close();

// Send/receive data
let data = client.receive(1024);
client.send("Hello, client!");

High-Level HTTP Client

import network.http;
import system.io;

fn fetch_webpage() -> ResultError> {
    // Create HTTP client
    let client = http.Client::new();
    
    // Configure request
    let request = http.Request::get("https://example.com")
        .header("User-Agent", "SystemScript/1.0")
        .timeout(30); // 30 seconds
    
    // Execute request
    let response = client.send(request)?;
    
    // Check status
    if (response.status != 200) {
        return Err(Error::HttpError(response.status));
    }
    
    // Return response body
    return Ok(response.body_text());
}

Security Features

SystemScript includes comprehensive security features for safe system programming:

Sandboxing and Privilege Management

import security.sandbox;

// Create restricted execution environment
let sandbox = sandbox.create();

// Restrict capabilities
sandbox.restrict_syscalls([syscall.OPEN, syscall.READ, syscall.WRITE, syscall.CLOSE]);
sandbox.set_memory_limit(100 * 1024 * 1024);  // 100MB
sandbox.restrict_network_access();

// Execute code in sandbox
sandbox.run(|| {
    // Code runs with restricted privileges
});

Memory Protection

import security.memory;

// Create protected memory region
let protected_buffer = memory.secure_alloc(1024);
defer memory.secure_free(protected_buffer);

// Protect sensitive data
memory.secure_zero(password_buffer, password_length);

// Create execute-only memory
let code_page = memory.alloc_executable(4096);
memory.make_execute_only(code_page);

Cryptography

import security.crypto;

// Hash functions
let hash = crypto.sha256("Data to hash");

// Symmetric encryption
let key = crypto.generate_key(crypto.AES_256);
let encrypted = crypto.encrypt(data, key, crypto.AES_GCM);
let decrypted = crypto.decrypt(encrypted, key, crypto.AES_GCM);

// Asymmetric encryption
let keypair = crypto.generate_keypair(crypto.RSA_2048);
let signature = crypto.sign(data, keypair.private);
let valid = crypto.verify(data, signature, keypair.public);

System Calls

SystemScript provides direct access to system calls across different platforms:

System Call Interface

import system.syscall;

// Direct system call invocation
fn custom_write(fd: i32, buffer: *u8, size: size_t) -> ssize_t {
    // Linux x86_64 write syscall
    #[cfg(target_os = "linux", target_arch = "x86_64")]
    return syscall.invoke(1, fd, buffer, size);
    
    // Linux arm64 write syscall
    #[cfg(target_os = "linux", target_arch = "arm64")]
    return syscall.invoke(64, fd, buffer, size);
    
    // Windows-specific implementation using NtWriteFile
    #[cfg(target_os = "windows")]
    return syscall.nt_write_file(fd, buffer, size);
}

Platform-Specific System Interfaces

// Linux-specific code
#[cfg(target_os = "linux")]
fn setup_io_uring() {
    import linux.io_uring;
    
    let ring = io_uring.setup(128);
    // Configure IO_URING
}

// Windows-specific code
#[cfg(target_os = "windows")]
fn setup_io_completion_port() {
    import windows.iocp;
    
    let iocp = iocp.create();
    // Configure IOCP
}

Concurrency & Parallelism

SystemScript provides comprehensive concurrency primitives for multi-threaded and parallel programming:

Thread Management

import concurrency.thread;

// Create thread
let thread = thread.spawn(|| {
    // Thread code
    for (let i = 0; i < 1000; i++) {
        // Do work
    }
});

// Wait for thread completion
thread.join();

// Thread pool
let pool = thread.create_pool(num_cores);
pool.submit(task1);
pool.submit(task2);
pool.wait_all();

Synchronization Primitives

import concurrency.sync;

// Mutex
let mutex = sync.Mutex::new();
mutex.lock();
// Critical section
mutex.unlock();

// Read-write lock
let rwlock = sync.RwLock::new();
{
    let reader = rwlock.read_lock();
    // Multiple readers can access
}
{
    let writer = rwlock.write_lock();
    // Exclusive writer access
}

// Atomic operations
let counter = atomic<i32>(0);
counter.fetch_add(1);
counter.compare_exchange(10, 20);

High-Level Concurrency

import concurrency.async;

// Futures and promises
let promise = async.Promise<i32>::new();
promise.set_value(42);
let future = promise.get_future();
let value = future.wait();

// Async/await
async fn fetch_data(url: str) -> ResultError> {
    let response = await http.get(url);
    return process_response(response);
}

// Task scheduling
let scheduler = async.Scheduler::new(4);  // 4 worker threads
scheduler.schedule(fetch_data("https://example.com"));

// Coroutines
fn coroutine() -> Generator<i32> {
    yield 1;
    yield 2;
    yield 3;
}

for (value in coroutine()) {
    io.println(value);
}

import concurrency.thread;
import system.io;

fn main() {
    let nums = [1, 2, 3, 4, 5, 6, 7, 8];
    let results = parallel_map(nums, |x| x * x);
    
    for (i in 0..nums.length) {
        io.println("{} squared = {}", nums[i], results[i]);
    }
}

fn parallel_map<T, R>(items: [T], func: fn(T) -> R) -> [R] {
    let results = [R; items.length];
    let threads = [];
    
    for (i in 0..items.length) {
        let item = items[i];
        let thread = thread.spawn(|| {
            return func(item);
        });
        threads.push(thread);
    }
    
    for (i in 0..threads.length) {
        results[i] = threads[i].join();
    }
    
    return results;
}

Metaprogramming

SystemScript provides powerful compile-time metaprogramming capabilities:

Compile-Time Function Execution

#[comptime]
fn generate_lookup_table() -> [i32; 256] {
    let table: [i32; 256];
    for (let i = 0; i < 256; i++) {
        table[i] = i * i;
    }
    return table;
}

// Table is computed at compile time
const SQUARES = generate_lookup_table();

Code Generation

// Generate struct field accessors
#[generate_accessors]
struct User {
    id: i32,
    name: str,
    email: str
}

// Use generated code
let user = User { id: 1, name: "John", email: "john@example.com" };
let id = user.get_id();
user.set_name("John Doe");

Reflection

import meta;

// Get type information at runtime
let type_info = meta.type_of<User>();
for (field in type_info.fields) {
    io.println("Field: " + field.name + ", Type: " + field.type.name);
}

// Dynamic instance creation
let instance = meta.create<User>();
meta.set_field(instance, "name", "Dynamic User");

Custom DSLs

// Define a simple query DSL
#[dsl]
fn sql_query(query_string: str) -> Query {
    // Parse and validate at compile time
    // Transform to safe SQL operations
}

// Use the DSL
let users = sql_query("""
    SELECT id, name, email
    FROM users
    WHERE age > 18
    ORDER BY name
""");

JIT Compilation

SystemScript includes a just-in-time compilation system for dynamic code generation:

Dynamic Code Generation

import jit;

// Create JIT compiler
let compiler = jit.Compiler::new();

// Add function to compile
compiler.add_function<fn(i32) -> i32>("square", "
    fn square(x: i32) -> i32 {
        return x * x;
    }
");

// Compile and get function pointer
let square_fn = compiler.compile<fn(i32) -> i32>("square");

// Execute dynamically compiled function
let result = square_fn(5);  // 25

Low-Level Code Generation

import jit.assembler;

// Create assembler
let asm = assembler.create(assembler.X86_64);

// Generate machine code
asm.mov(assembler.RAX, assembler.RDI);  // First argument to RAX
asm.imul(assembler.RAX, assembler.RAX); // Square it
asm.ret();                             // Return

// Finalize and execute
let square_fn = asm.finalize<fn(i32) -> i32>();
let result = square_fn(5);  // 25

Runtime Optimization

import jit.optimizer;

// Create a function trace recorder
let tracer = optimizer.trace_recorder();

// Start recording a function execution
tracer.start("hot_function");

// Execute the function with sample input
hot_function(10, "test");

// Stop recording and optimize
let optimized_fn = tracer.finish_and_optimize();

// Replace the original function with the optimized version
optimizer.install(optimized_fn);

Inline Assembly

SystemScript allows embedding assembly code directly in the program:

Basic Inline Assembly

fn cpuid() -> (u32, u32, u32, u32) {
    let eax: u32 = 1;
    let ebx: u32 = 0;
    let ecx: u32 = 0;
    let edx: u32 = 0;
    
    asm {
        "cpuid"
        : "=a"(eax), "=b"(ebx), "=c"(ecx), "=d"(edx)
        : "a"(eax)
        : "memory"
    }
    
    return (eax, ebx, ecx, edx);
}

Architecture-Specific Assembly

// x86_64 specific inline assembly
#[cfg(target_arch = "x86_64")]
fn read_tsc() -> u64 {
    let low: u32;
    let high: u32;
    
    asm {
        "rdtsc"
        : "=a"(low), "=d"(high)
        :
        : "memory"
    }
    
    return (high as u64) << 32 | (low as u64);
}

// ARM64 specific inline assembly
#[cfg(target_arch = "arm64")]
fn read_tsc() -> u64 {
    let result: u64;
    
    asm {
        "mrs %0, CNTVCT_EL0"
        : "=r"(result)
        :
        :
    }
    
    return result;
}

SIMD Instructions

import hardware.simd;

// SIMD vector addition using inline assembly
fn vector_add_asm(a: *f32, b: *f32, result: *f32, length: usize) {
    for (let i = 0; i < length; i += 4) {
        asm {
            "movups xmm0, [%1]
             movups xmm1, [%2]
             addps xmm0, xmm1
             movups [%0], xmm0"
            : 
            : "r"(result + i), "r"(a + i), "r"(b + i)
            : "xmm0", "xmm1", "memory"
        }
    }
}

// Higher-level SIMD API
fn vector_add_api(a: *f32, b: *f32, result: *f32, length: usize) {
    for (let i = 0; i < length; i += 4) {
        let va = simd.load_f32x4(a + i);
        let vb = simd.load_f32x4(b + i);
        let vresult = simd.add_f32x4(va, vb);
        simd.store_f32x4(result + i, vresult);
    }
}

Kernel Development

SystemScript provides features specifically designed for operating system kernel development:

// Simple kernel entry point
#[no_mangle]
extern "C" fn kernel_main() {
    // Initialize console
    terminal.initialize();
    terminal.print("SystemScript Kernel booting...\n");
    
    // Initialize descriptor tables
    gdt.initialize();
    idt.initialize();
    
    // Initialize memory management
    physical_memory.initialize();
    virtual_memory.initialize();
    
    // Initialize device drivers
    drivers.initialize();
    
    // Enable interrupts
    cpu.enable_interrupts();
    
    // Initialize scheduler
    scheduler.initialize();
    
    // Create initial process
    let init_process = process.create(init_task);
    scheduler.start();
    
    // Should never reach here
    panic("Kernel returned from scheduler");
}

// Interrupt handler
#[interrupt_handler]
fn page_fault_handler(frame: &InterruptFrame) {
    let fault_address = cpu.read_cr2();
    let error_code = frame.error_code;
    
    if (can_handle_page_fault(fault_address, error_code)) {
        // Map a new page
        handle_page_fault(fault_address);
    } else {
        panic("Unhandled page fault at address " + fault_address);
    }
}

Device Drivers

SystemScript provides a comprehensive framework for device driver development:

// PCI device driver
struct PciDevice : Driver {
    vendor_id: u16;
    device_id: u16;
    pci_address: u32;
    irq: u8;
    
    // Driver interface implementation
    fn probe() -> bool {
        // Check if device exists
        return pci.device_exists(vendor_id, device_id);
    }
    
    fn initialize() -> Result<(), Error> {
        // Find device
        pci_address = pci.find_device(vendor_id, device_id);
        
        // Enable bus mastering
        pci.enable_bus_mastering(pci_address);
        
        // Map device memory
        let bar0 = pci.read_bar(pci_address, 0);
        registers = mmio.map(bar0, 4096);
        
        // Set up interrupt handler
        irq = pci.get_interrupt_line(pci_address);
        interrupts.register_handler(irq, handle_interrupt);
        
        return Ok(());
    }
    
    fn shutdown() {
        // Disable device
        // Free resources
    }
    
    fn handle_interrupt(frame: &InterruptFrame) {
        // Handle device interrupt
        let status = registers[0x00];
        if (status & 0x01) {
            // Process interrupt
        }
        
        // Acknowledge interrupt
        registers[0x00] = status;
    }
}

Web Development

SystemScript provides comprehensive tools for web development, from low-level HTTP handling to high-level web frameworks:

import web.http;
import web.router;

// Define a simple web application
let app = web.Application::new();

// Define routes
app.route("/", method: http.GET, handler: handle_home);
app.route("/api/users", method: http.GET, handler: get_users);
app.route("/api/users", method: http.POST, handler: create_user);

// Start server
app.listen("0.0.0.0", 8080);

// Route handler
fn handle_home(req: &http.Request, res: &http.Response) {
    res.content_type = "text/html";
    res.write("
Hello from SystemScript!
");
}

// JSON API handler
fn get_users(req: &http.Request, res: &http.Response) {
    // Get users from database
    let users = db.query("SELECT * FROM users");
    
    // Return as JSON
    res.content_type = "application/json";
    res.write(json.stringify(users));
}

// Process form submission
fn create_user(req: &http.Request, res: &http.Response) {
    // Parse JSON body
    let data = json.parse(req.body);
    
    // Validate input
    if (!data.has("name") || !data.has("email")) {
        res.status = 400;
        res.write(json.stringify({ error: "Invalid input" }));
        return;
    }
    
    // Create user
    let user_id = db.execute(
        "INSERT INTO users (name, email) VALUES (?, ?)",
        [data.name, data.email]
    );
    
    // Return success response
    res.status = 201;
    res.write(json.stringify({ id: user_id }));
}

Network Programming

SystemScript provides tools for developing network applications and protocols at any level of abstraction:

import network.protocol;
                import network.packet;
                
                // Define custom network protocol
                struct MyProtocol {
                    // Protocol header
                    struct Header {
                        version: u8;
                        type: u8;
                        length: u16;
                        sequence: u32;
                        checksum: u32;
                    }
                    
                    // Protocol implementation
                    fn parse_packet(data: &[u8]) -> ResultError> {
                        if (data.length < sizeof(Header)) {
                            return Err(Error::InvalidFormat);
                        }
                        
                        let header = data.reinterpret<Header>(0);
                        
                        // Verify packet
                        if (header.version != 1) {
                            return Err(Error::UnsupportedVersion);
                        }
                        
                        // Verify checksum
                        let computed_checksum = calculate_checksum(data, header.length);
                        if (computed_checksum != header.checksum) {
                            return Err(Error::InvalidChecksum);
                        }
                        
                        // Extract payload
                        let payload = data.slice(sizeof(Header), header.length);
                        
                        return Ok(Packet { header, payload });
                    }
                    
                    fn create_packet(type: u8, payload: &[u8]) -> [u8] {
                        let total_length = sizeof(Header) + payload.length;
                        let packet = [u8; total_length];
                        
                        // Create header
                        let header = packet.reinterpret<Header>(0);
                        header.version = 1;
                        header.type = type;
                        header.length = payload.length as u16;
                        header.sequence = next_sequence();
                        
                        // Copy payload
                        packet.copy_from(payload, sizeof(Header));
                        
                        // Calculate and set checksum
                        header.checksum = calculate_checksum(packet, total_length);
                        
                        return packet;
                    }
                }

Raw Socket Programming

import network.raw;
                import network.ethernet;
                
                // Create a raw socket bound to a specific interface
                fn packet_sniffer() {
                    // Open raw socket on interface eth0
                    let socket = raw.create_socket("eth0", raw.ETH_P_ALL);
                    defer socket.close();
                    
                    // Set promiscuous mode
                    socket.set_promiscuous(true);
                    
                    // Create buffer for incoming packets
                    let buffer = [u8; 9000];  // Jumbo frame size
                    
                    while (true) {
                        // Receive packet
                        let bytes = socket.receive(buffer);
                        
                        if (bytes > 0) {
                            // Parse Ethernet frame
                            let frame = ethernet.parse_frame(buffer, bytes);
                            
                            // Process based on Ethernet type
                            switch (frame.ethertype) {
                                case ethernet.ETH_P_IP:
                                    process_ip_packet(frame.payload);
                                    break;
                                case ethernet.ETH_P_ARP:
                                    process_arp_packet(frame.payload);
                                    break;
                                default:
                                    // Unknown protocol
                                    break;
                            }
                        }
                    }
                }

Protocol Implementation

import network.tcp;
                import system.io;
                
                // Implement a simple TCP client
                fn connect_to_server(address: str, port: u16) -> ResultError> {
                    // Create TCP connection
                    let stream = tcp.connect(address, port)?;
                    
                    // Configure TCP options
                    stream.set_nodelay(true);  // Disable Nagle's algorithm
                    stream.set_keepalive(true, 60);  // Enable keepalive with 60s timeout
                    
                    // Send HTTP request
                    let request = "GET / HTTP/1.1\r\nHost: " + address + "\r\nConnection: close\r\n\r\n";
                    stream.write(request)?;
                    
                    // Read response
                    let response = stream.read_to_string()?;
                    io.println("Received {} bytes", response.length);
                    
                    return Ok(stream);
                }

Custom Network Stack

SystemScript allows you to implement custom network stacks for specialized applications:

module custom_network_stack;
                
                import hardware.nic;
                import network.raw;
                import memory.dma;
                
                // Network interface driver
                struct NetworkInterface {
                    device: *nic.Device;
                    rx_ring: dma.RingBuffer;
                    tx_ring: dma.RingBuffer;
                    mtu: u16;
                    mac_address: [u8; 6];
                    
                    // Initialize network interface
                    fn initialize(device_id: str) -> Result<(), Error> {
                        // Open network device
                        device = nic.open(device_id)?;
                        
                        // Get device capabilities
                        let caps = device.get_capabilities();
                        
                        // Set up DMA rings for zero-copy networking
                        rx_ring = dma.create_ring(device, 256, 2048, dma.DIRECTION_RX);
                        tx_ring = dma.create_ring(device, 256, 2048, dma.DIRECTION_TX);
                        
                        // Get interface properties
                        mtu = device.get_mtu();
                        mac_address = device.get_mac_address();
                        
                        // Enable device
                        device.enable();
                        
                        return Ok(());
                    }
                    
                    // Send packet through interface
                    fn send_packet(packet: &[u8]) -> Result<(), Error> {
                        // Get free buffer from TX ring
                        let buffer = tx_ring.get_free_buffer()?;
                        
                        // Copy packet to DMA buffer
                        memory.copy(buffer.data, packet.data, packet.length);
                        buffer.length = packet.length;
                        
                        // Submit buffer to NIC for transmission
                        tx_ring.submit_buffer(buffer);
                        
                        // Notify device about new TX packet
                        device.notify_tx();
                        
                        return Ok(());
                    }
                    
                    // Receive packets from interface
                    fn receive_packets(callback: fn(&[u8])) {
                        // Process all available packets in RX ring
                        while (let buffer = rx_ring.get_next_received()) {
                            // Process packet through callback
                            callback(buffer.data.slice(0, buffer.length));
                            
                            // Return buffer to RX ring
                            rx_ring.return_buffer(buffer);
                        }
                    }
                }

Security Research

SystemScript provides tools for security research and vulnerability analysis, enabling both offensive and defensive security development:

Vulnerability Detection

import security.analysis;
                import memory.protection;
                
                // Detect buffer overflow vulnerabilities
                fn check_buffer_overflow(binary_path: str) {
                    let binary = analysis.load_binary(binary_path);
                    
                    // Find stack buffer allocations
                    let stack_buffers = binary.find_stack_buffers();
                    
                    for (buffer in stack_buffers) {
                        // Check for bounds checking
                        if (!buffer.has_bounds_checking()) {
                            io.println("Potential buffer overflow in function: " + buffer.function);
                            io.println("  Buffer size: " + buffer.size);
                            io.println("  Access patterns: " + buffer.access_patterns);
                        }
                    }
                }
                
                // Memory corruption detection
                fn detect_memory_corruption() {
                    // Create protected memory regions
                    let canary_before = protection.create_canary_page();
                    let buffer = memory.alloc(1024);
                    let canary_after = protection.create_canary_page();
                    
                    // Set up handlers
                    protection.on_violation(canary_before, || {
                        panic("Buffer underflow detected");
                    });
                    
                    protection.on_violation(canary_after, || {
                        panic("Buffer overflow detected");
                    });
                    
                    // Use buffer
                    test_function(buffer);
                }

Binary Analysis

import security.binary;
                import security.disasm;
                import system.io;
                
                fn analyze_binary(path: str) {
                    // Load binary
                    let binary = binary.load(path);
                    io.println("Loaded binary: {}", path);
                    
                    // Analyze binary properties
                    io.println("Architecture: {}", binary.architecture);
                    io.println("Entry point: 0x{:X}", binary.entry_point);
                    
                    // Check security features
                    io.println("ASLR: {}", binary.has_aslr());
                    io.println("NX: {}", binary.has_nx());
                    io.println("Stack canaries: {}", binary.has_stack_canary());
                    
                    // Find functions
                    let functions = binary.find_functions();
                    io.println("Found {} functions", functions.length);
                    
                    // Examine a specific function
                    if (let main = binary.find_function("main")) {
                        io.println("\nDisassembling main function:");
                        let disasm = disasm.disassemble(binary, main.address, main.size);
                        
                        for (instruction in disasm.instructions) {
                            io.println("0x{:X}: {} {}", instruction.address, 
                                      instruction.mnemonic, instruction.op_str);
                        }
                    }
                }

Exploit Development

import security.exploit;
                import memory.patcher;
                
                // Develop proof-of-concept exploit
                fn create_poc(vulnerability_type: str, target_binary: str) -> ResultError> {
                    // Create exploit framework
                    let exploit = exploit.create(vulnerability_type);
                    
                    // Configure target
                    exploit.set_target(target_binary);
                    
                    switch (vulnerability_type) {
                        case "buffer-overflow":
                            // Generate pattern to find offset
                            let pattern = exploit.generate_pattern(1024);
                            
                            // Find offset to return address
                            let offset = exploit.find_offset();
                            
                            // Create payload
                            let payload = [u8; offset + 8];
                            
                            // Fill buffer with padding
                            memory.set(payload, 'A' as u8, offset);
                            
                            // Add return address override
                            let ret_addr = exploit.find_gadget("pop rdi; ret");
                            memory.copy_u64_le(payload.offset(offset), ret_addr);
                            
                            exploit.set_payload(payload);
                            break;
                            
                        case "format-string":
                            // Create format string exploit
                            let got_addr = exploit.find_got_entry("printf");
                            let payload = exploit.create_format_string(got_addr);
                            exploit.set_payload(payload);
                            break;
                            
                        default:
                            return Err(Error::UnsupportedExploitType);
                    }
                    
                    // Validate exploit
                    if (!exploit.validate()) {
                        return Err(Error::InvalidExploit);
                    }
                    
                    return Ok(exploit);
                }

Defensive Security

SystemScript also enables the development of defensive security tools:

import security.monitor;
                import security.ids;
                import network.packet;
                
                // Network Intrusion Detection System
                struct NetworkIDS {
                    rules: [ids.Rule];
                    interfaces: [str];
                    packet_processors: [PacketProcessor];
                    running: bool;
                    
                    fn initialize(rule_file: str, interfaces: [str]) -> Result<(), Error> {
                        // Load detection rules
                        rules = ids.load_rules(rule_file)?;
                        this.interfaces = interfaces;
                        
                        // Create packet processors for each interface
                        for (iface in interfaces) {
                            let processor = PacketProcessor::new(iface);
                            packet_processors.push(processor);
                        }
                        
                        return Ok(());
                    }
                    
                    fn start() {
                        running = true;
                        
                        // Start packet processors
                        for (processor in packet_processors) {
                            processor.start(process_packet);
                        }
                    }
                    
                    fn stop() {
                        running = false;
                        
                        // Stop packet processors
                        for (processor in packet_processors) {
                            processor.stop();
                        }
                    }
                    
                    fn process_packet(packet: &packet.Packet) {
                        // Check packet against rules
                        for (rule in rules) {
                            if (rule.matches(packet)) {
                                // Alert on match
                                alert(rule, packet);
                                
                                // Take action based on rule
                                if (rule.action == ids.ACTION_BLOCK) {
                                    block_source(packet.source_ip);
                                }
                            }
                        }
                    }
                    
                    fn alert(rule: &ids.Rule, packet: &packet.Packet) {
                        // Generate alert
                        let alert = ids.Alert {
                            timestamp: system.time(),
                            rule_id: rule.id,
                            severity: rule.severity,
                            source_ip: packet.source_ip,
                            dest_ip: packet.dest_ip,
                            protocol: packet.protocol,
                            description: rule.description
                        };
                        
                        // Log alert
                        ids.log_alert(alert);
                    }
                }

Binary Patching and Hardening

import security.patch;
                import security.binary;
                
                // Patch binary to fix vulnerability
                fn patch_binary(path: str) -> Result<(), Error> {
                    // Load binary
                    let binary = binary.load(path);
                    
                    // Find vulnerable function
                    let target_function = binary.find_function("vulnerable_function")?;
                    
                    // Find buffer overflow vulnerability
                    let vuln = target_function.find_pattern([
                        0x48, 0x89, 0xe5,             // mov rbp, rsp
                        0x48, 0x83, 0xec, 0x20,       // sub rsp, 0x20
                        0xe8, 0x00, 0x00, 0x00, 0x00    // call strcpy
                    ])?;
                    
                    // Create safer replacement code
                    let safe_code = patch.create_code([
                        0x48, 0x89, 0xe5,             // mov rbp, rsp
                        0x48, 0x83, 0xec, 0x20,       // sub rsp, 0x20
                        0xe8, 0x00, 0x00, 0x00, 0x00    // call strncpy
                    ]);
                    
                    // Fix call reference to strncpy
                    let strncpy_addr = binary.get_plt_entry("strncpy");
                    patch.fix_relative_call(safe_code.offset(7), vuln.address + 7, strncpy_addr);
                    
                    // Apply patch
                    binary.patch(vuln.address, safe_code);
                    
                    // Add additional hardening
                    binary.enable_nx();
                    binary.enable_aslr();
                    binary.enable_stack_protection();
                    binary.enable_relro();
                    
                    // Save patched binary
                    binary.save(path + ".patched");
                    
                    return Ok(());
                }

Hello World

module hello_world;

import system.io;

fn main() -> i32 {
    io.println("Hello, SystemScript World!");
    return 0;
}

Minimal Kernel

module kernel;

import hardware.cpu;
import hardware.terminal;
import system.interrupts;
import memory.virtual;

// Kernel entry point
#[no_mangle]
#[export]
fn kernel_main() {
    // Initialize terminal for output
    terminal.initialize();
    terminal.clear();
    terminal.print("SystemScript Kernel\n");
    
    // Initialize GDT and IDT
    cpu.setup_gdt();
    interrupts.setup_idt();
    
    // Setup memory management
    virtual.initialize();
    
    // Setup interrupt handlers
    interrupts.set_handler(0x0E, page_fault_handler);
    interrupts.enable();
    
    // Kernel main loop
    loop {
        cpu.halt();
    }
}

Memory Management

module memory_manager;

import memory;
import system.io;

// Custom memory allocator
struct BlockAllocator {
    memory_start: *u8;
    memory_size: size_t;
    free_list: *BlockHeader;
    
    struct BlockHeader {
        size: size_t;
        next: *BlockHeader;
        free: bool;
    }
    
    // Initialize allocator with memory region
    fn initialize(start: *u8, size: size_t) {
        memory_start = start;
        memory_size = size;
        
        // Create initial free block
        free_list = start as *BlockHeader;
        free_list.size = size - sizeof(BlockHeader);
        free_list.next = null;
        free_list.free = true;
    }
    
    // Allocate memory
    fn alloc(size: size_t) -> *u8 {
        // Align size to 8 bytes
        let aligned_size = (size + 7) & ~7;
        
        // Find suitable block
        let current = free_list;
        let prev: *BlockHeader = null;
        
        while (current != null) {
            if (current.free && current.size >= aligned_size) {
                // Found a block
                
                // Split if large enough
                if (current.size >= aligned_size + sizeof(BlockHeader) + 16) {
                    // Create new free block
                    let new_block = (current as *u8 + sizeof(BlockHeader) + aligned_size) as *BlockHeader;
                    new_block.size = current.size - aligned_size - sizeof(BlockHeader);
                    new_block.next = current.next;
                    new_block.free = true;
                    
                    // Update current block
                    current.size = aligned_size;
                    current.next = new_block;
                }
                
                // Mark as used
                current.free = false;
                
                // Return pointer to data
                return (current as *u8) + sizeof(BlockHeader);
            }
            
            prev = current;
            current = current.next;
        }
        
        // No suitable block found
        return null;
    }
    
    // Free memory
    fn free(ptr: *u8) {
        if (ptr == null) return;
        
        // Get block header
        let block = (ptr - sizeof(BlockHeader)) as *BlockHeader;
        
        // Mark as free
        block.free = true;
        
        // Coalesce with next block if free
        if (block.next != null && block.next.free) {
            block.size += sizeof(BlockHeader) + block.next.size;
            block.next = block.next.next;
        }
    }
}

Device Driver

module usb_driver;

import hardware.pci;
import hardware.usb;
import hardware.interrupts;
import memory.mmio;
import system.io;

// USB Host Controller Driver
struct UhciDriver {
    base_address: u32;
    registers: *[u32];
    irq: u8;
    
    // Command register bits
    const CMD_RUN = 0x0001;
    const CMD_RESET = 0x0002;
    const CMD_GLOBAL_RESET = 0x0004;
    
    // Status register bits
    const STS_INTERRUPT = 0x0001;
    const STS_ERROR = 0x0002;
    const STS_HALTED = 0x0020;
    
    // Initialize the driver
    fn initialize() -> bool {
        // Find UHCI controller on PCI bus
        let pci_addr = pci.find_device(0x8086, 0x7112);  // Intel UHCI
        if (pci_addr == 0xFFFFFFFF) {
            io.println("UHCI controller not found");
            return false;
        }
        
        // Get I/O base address
        base_address = pci.read_bar(pci_addr, 0) & ~0x0F;
        io.println("UHCI base address: " + base_address);
        
        // Get IRQ
        irq = pci.read_config_byte(pci_addr, 0x3C);
        io.println("UHCI IRQ: " + irq);
        
        // Enable PCI bus mastering
        let command = pci.read_config_word(pci_addr, 0x04);
        pci.write_config_word(pci_addr, 0x04, command | 0x0004);
        
        // Register interrupt handler
        interrupts.register_handler(irq, handle_interrupt);
        
        // Reset the controller
        reset();
        
        // Initialize data structures
        setup_frame_list();
        
        // Start the controller
        start();
        
        return true;
    }
    
    // Reset the controller
    fn reset() {
        // Global reset
        io.port_write<u16>(base_address + 2, CMD_GLOBAL_RESET);
        system.sleep(50);  // Wait 50ms
        io.port_write<u16>(base_address + 2, 0);
        
        // Controller reset
        io.port_write<u16>(base_address + 2, CMD_RESET);
        system.sleep(10);  // Wait 10ms
        io.port_write<u16>(base_address + 2, 0);
    }
}

Web Server

module simple_web_server;

import network.socket;
import network.address;
import network.http;
import system.io;
import concurrency.thread;

// Simple HTTP web server
struct WebServer {
    socket: Socket;
    port: u16;
    running: bool;
    
    // Initialize the server
    fn initialize(port: u16) -> bool {
        this.port = port;
        
        // Create socket
        socket = socket.create(socket.AF_INET, socket.SOCK_STREAM);
        if (!socket.is_valid()) {
            io.println("Failed to create socket");
            return false;
        }
        
        // Set socket options
        socket.set_option(socket.SO_REUSEADDR, true);
        
        // Bind to address
        let addr = Address {
            family: socket.AF_INET,
            port: port,
            address: [0, 0, 0, 0]  // 0.0.0.0
        };
        
        if (!socket.bind(addr)) {
            io.println("Failed to bind to port " + port);
            return false;
        }
        
        // Listen for connections
        if (!socket.listen(10)) {
            io.println("Failed to listen on socket");
            return false;
        }
        
        io.println("Server initialized on port " + port);
        return true;
    }
    
    // Start the server
    fn start() {
        running = true;
        
        io.println("Server started, waiting for connections...");
        
        while (running) {
            // Accept connection
            let client = socket.accept();
            if (!client.is_valid()) {
                continue;
            }
            
            // Handle client in a new thread
            thread.spawn(|| {
                handle_client(client);
            });
        }
    }
    
    // Handle client connection
    fn handle_client(client: Socket) {
        defer client.close();
        
        // Read request
        let buffer = [u8; 4096];
        let bytes_read = client.receive(buffer, 4096);
        
        if (bytes_read <= 0) {
            return;
        }
        
        // Parse HTTP request
        let request = http.parse_request(buffer, bytes_read);
        
        // Log request
        io.println(request.method + " " + request.path);
        
        // Generate response
        let response: str;
        
        if (request.path == "/") {
            response = "HTTP/1.1 200 OK\r\n"
                     + "Content-Type: text/html\r\n"
                     + "Connection: close\r\n"
                     + "\r\n"
                     + "\r\n"
                     + "\r\n"
                     + "
Welcome to SystemScript Web Server
\r\n"
                     + "
This is a simple web server implementation.
\r\n"
                     + "";
        } else {
            response = "HTTP/1.1 404 Not Found\r\n"
                     + "Content-Type: text/html\r\n"
                     + "Connection: close\r\n"
                     + "\r\n"
                     + "\r\n"
                     + "\r\n"
                     + "
404 Not Found
\r\n"
                     + "
The requested page was not found.
\r\n"
                     + "";
        }
        
        // Send response
        client.send(response);
    }
}

Network Protocol

module custom_protocol;

import network.socket;
import network.raw;
import system.io;

// Custom network protocol
struct CustomProtocol {
    // Protocol header (little-endian)
    #[packed]
    struct Header {
        magic: [u8; 4];     // "CSPL"
        version: u8;        // Protocol version
        type: u8;           // Message type
        flags: u16;         // Flags
        length: u32;        // Payload length
        sequence: u32;      // Sequence number
        checksum: u32;      // CRC32 checksum
    }
    
    // Message types
    const TYPE_CONNECT = 0x01;
    const TYPE_DATA = 0x02;
    const TYPE_ACK = 0x03;
    const TYPE_DISCONNECT = 0x04;
    
    // Flag values
    const FLAG_ENCRYPTED = 0x0001;
    const FLAG_COMPRESSED = 0x0002;
    const FLAG_URGENT = 0x0004;
    
    // Current sequence number
    static sequence: u32 = 0;
    
    // Calculate CRC32 checksum
    fn calculate_checksum(data: &[u8], length: u32) -> u32 {
        let crc: u32 = 0xFFFFFFFF;
        
        for (let i = 0; i < length; i++) {
            let byte = data[i];
            crc ^= byte;
            
            for (let j = 0; j < 8; j++) {
                if (crc & 1) {
                    crc = (crc >> 1) ^ 0xEDB88320;
                } else {
                    crc = crc >> 1;
                }
            }
        }
        
        return ~crc;
    }
    
    // Create a packet
    fn create_packet(type: u8, flags: u16, payload: &[u8]) -> [u8] {
        let header_size = sizeof(Header);
        let total_size = header_size + payload.length;
        
        let packet = [u8; total_size];
        let header = packet.reinterpret<Header>(0);
        
        // Set header fields
        header.magic = ['C', 'S', 'P', 'L'];
        header.version = 1;
        header.type = type;
        header.flags = flags;
        header.length = payload.length;
        header.sequence = sequence++;
        header.checksum = 0;  // Will be set later
        
        // Copy payload
        if (payload.length > 0) {
            memory.copy(packet.offset(header_size), payload.data, payload.length);
        }
        
        // Calculate and set checksum (excluding checksum field itself)
        header.checksum = calculate_checksum(packet, total_size);
        
        return packet;
    }
}

Compiler

The SystemScript compiler (ssc) translates SystemScript code into optimized machine code:

# Basic compilation
ssc -o program source.ss

# Compile with optimization level
ssc -O3 -o program source.ss

# Target specific architecture
ssc --target=x86_64 -o program source.ss

# Generate debug information
ssc -g -o program source.ss

# Enable specific features
ssc --enable-unsafe --enable-jit -o program source.ss

# Compile to library
ssc --lib -o libexample.so source.ss

# Compile with specific safety level
ssc --safety=strict -o program source.ss

Linker

The SystemScript linker (ssl) combines multiple object files into executables or libraries:

# Link object files
ssl -o program main.o utils.o

# Link with libraries
ssl -o program main.o -L/usr/lib -lsystemio

# Create a dynamic library
ssl --shared -o libcustom.so file1.o file2.o

# Link with custom entry point
ssl --entry=custom_main -o program main.o

# Link for kernel development
ssl --kernel -o kernel.bin entry.o memory.o

Debugger

The SystemScript debugger (ssd) provides powerful debugging capabilities:

# Start debugger
ssd program

# Start with arguments
ssd program arg1 arg2

# Debugger commands
(ssd) break main         # Set breakpoint at main
(ssd) break file.ss:42   # Set breakpoint at line 42
(ssd) run                # Run program
(ssd) step               # Step into
(ssd) next               # Step over
(ssd) continue           # Continue execution
(ssd) print variable     # Print variable value
(ssd) backtrace          # Show call stack
(ssd) memory 0x1000 32   # Examine memory
(ssd) disasm             # Disassemble current function
(ssd) registers          # Show CPU registers
(ssd) watch *ptr         # Set memory watchpoint

// Sample program to debug
fn factorial(n: i32) -> i32 {
    if (n <= 1) {
        return 1;
    } else {
        return n * factorial(n - 1);
    }
}

fn main() {
    let result = factorial(5);
    io.println("Factorial of 5 is: {}", result);
}

Build System

SystemScript includes a powerful build system (ssb) for managing complex projects:

# Initialize project
ssb init --name=myproject

# Build project
ssb build

# Clean project
ssb clean

# Run tests
ssb test

# Package for distribution
ssb package

# Project configuration (project.ss)
project "MyProject" {
    version = "1.0.0"
    authors = ["Your Name"]
    
    dependencies {
        "system-io" = "^2.0.0"
        "network" = "^1.5.0"
    }
    
    features {
        default = ["standard"]
        standard = []
        full = ["web", "crypto"]
        web = []
        crypto = []
    }
    
    targets {
        default {
            type = "executable"
            main = "src/main.ss"
        }
        
        lib {
            type = "library"
            crate-type = ["staticlib", "dylib"]
        }
    }
}