# Strategic Features - Complete Specifications

## Overview

This document provides detailed specifications for all 16 features, organized by category. Each feature includes:
- Executive summary
- Use cases
- Technical approach
- Implementation complexity
- Integration points
- Success criteria

## 🔐 Security Features (4)

### 1. `seal` - Immutable Objects ✅ IMPLEMENTED

**Status**: Complete in lexer, parser, AST, security module, and evaluator

**Overview**:
Create sealed (immutable) object instances that cannot be modified after creation.

**Syntax**:
```zexus
seal user;
```

**Use Cases**:
- Security contexts (credentials, keys)
- Compliance requirements (audit logs)
- Safe concurrent access
- Configuration objects

**How It Works**:
- Wrapped objects in `SealedObject` container
- Prevents `set` operations on sealed properties
- Enforces immutability at runtime
- Type information: `Sealed<ObjectType>`

**Testing Status**: ✅ Verified compiling in lexer, parser, AST, security module

---

### 2. `const` - Immutable Variables 🚀 IN PROGRESS

**Overview**:
Declare immutable variables at declaration time (like Java `final` or Rust immutable bindings).

**Syntax**:
```zexus
const MAX_USERS = 100;
const API_KEY = "abc123";
const ready = true;
```

**Use Cases**:
- Configuration constants
- Mathematical constants
- Prevent accidental reassignment
- Compiler optimization hints

**How It Works**:
1. Add `CONST` token to lexer
2. Extend parser to handle `const <identifier> = <expression>;`
3. Create `ConstStatement` AST node
4. Track const variables in environment
5. Prevent reassignment attempts
6. Allow const + const pattern: `const const x = 5;` (const sealed)

**Differences from `seal`**:
- `seal`: Seals existing objects/variables
- `const`: Makes variable immutable at declaration
- Can combine: `const seal x = {...}` = immutable const object

**Integration Points**:
- Lexer: Add CONST keyword
- Parser: Handle const statements
- AST: ConstStatement node
- Environment: Track const variables
- Evaluator: Prevent reassignment

**Implementation Complexity**: Low (1-2 days)

---

### 3. `audit` - Compliance Logging

**Overview**:
Automatically log all data access and modifications for compliance tracking (GDPR, SOX, etc.).

**Syntax**:
```zexus
let data = {name: "John", age: 30};
audit data;  // Now all reads/writes logged

// Logs:
// - All property accesses
// - All modifications
// - Timestamps
// - Caller information
```

**Use Cases**:
- Financial systems (SOX compliance)
- Healthcare systems (HIPAA compliance)
- Privacy regulations (GDPR compliance)
- Security incident analysis

**How It Works**:
1. Tracking mechanism in security module
2. Intercept all get/set operations
3. Log to audit trail (file, database)
4. Configuration for retention policies
5. Query audit logs

**Integration Points**:
- Security module: Audit trail manager
- Object.get/set: Audit hooks
- Logger: Audit output
- Configuration: Retention policies

**Implementation Complexity**: Medium (3-5 days)

---

### 4. `restrict` - Field-Level Access Control

**Overview**:
Restrict access to specific object fields based on roles/permissions.

**Syntax**:
```zexus
let user = {
  name: "John",
  salary: 50000,
  email: "john@example.com"
};

restrict user.salary to roles: ["admin"];
restrict user.email to roles: ["admin", "hr"];

// Now only admin/hr can read these fields
```

**Use Cases**:
- Multi-tenant systems
- Role-based access control (RBAC)
- Field-level privacy
- Data classification

**How It Works**:
1. Track field-level permissions
2. Validate caller's role on access
3. Throw error if unauthorized
4. Support wildcard patterns
5. Support role hierarchies

**Integration Points**:
- Security module: Permission checker
- Context: Current user/role
- Object.get: Permission validation
- Parser: restrict syntax

**Implementation Complexity**: Medium (4-6 days)

---

## ⚡ Performance Features (5)

### 5. `native` - C/C++ Integration

**Overview**:
Call native C/C++ functions directly from Zexus, enabling library integration and performance-critical code.

**Syntax**:
```zexus
native fn md5(data: buffer) -> string;
native fn uuid_generate() -> string;
native fn fast_sort(arr: []i64) -> []i64;

let hash = md5(buffer_data);
```

**Use Cases**:
- Crypto libraries (libsodium, OpenSSL)
- Math libraries (BLAS, LAPACK)
- Image processing (ImageMagick)
- Performance-critical algorithms
- Legacy library integration

**How It Works**:
1. FFI (Foreign Function Interface) layer
2. Generate C bindings
3. Dynamic library loading
4. Type marshalling (Zexus ↔ C)
5. Memory management coordination

**Integration Points**:
- Parser: native keyword
- Evaluator: FFI calls
- New module: FFI layer
- Config: Library paths

**Implementation Complexity**: High (7-10 days)

---

### 6. `gc` - Garbage Collection Control

**Overview**:
Explicit control over garbage collection behavior for performance optimization.

**Syntax**:
```zexus
gc pause;           // Suspend GC
// Performance-critical code
gc resume;          // Resume GC
gc collect;         // Force collection
gc stats;           // Print GC statistics
```

**Use Cases**:
- Latency-critical systems (trading, gaming)
- Real-time systems
- Performance-critical sections
- Memory profiling

**How It Works**:
1. Track GC state
2. Pause/resume mechanisms
3. Force collection
4. Statistics collection
5. GC parameters tuning

**Integration Points**:
- Evaluator: GC control
- Runtime: GC implementation
- Compiler: GC hints
- Statistics: GC metrics

**Implementation Complexity**: Medium (4-5 days)

---

### 7. `inline` - Function Inlining

**Overview**:
Hint compiler to inline functions for performance optimization.

**Syntax**:
```zexus
fn inline add(a: i64, b: i64) -> i64 {
  return a + b;
}

fn inline get_timeout() -> i64 {
  return CONFIG.timeout_ms;
}

// Compiler replaces calls with function body
let result = add(5, 3);  // Inlined: result = 5 + 3
```

**Use Cases**:
- Performance-critical hot loops
- Accessor functions
- Small utility functions
- Latency-sensitive code

**How It Works**:
1. Parser recognizes `inline` keyword
2. Mark function metadata
3. Compiler decision logic
4. Inline substitution during compilation
5. Performance metrics

**Integration Points**:
- Parser: inline keyword
- Compiler: inlining decisions
- AST: Function metadata
- Performance: Profiling

**Implementation Complexity**: Medium (5-6 days)

---

### 8. `buffer` - Direct Memory Access

**Overview**:
Direct memory buffer access for performance-critical code and FFI interop.

**Syntax**:
```zexus
let buf = buffer.allocate(1024);
buf.write_u32(0, 12345);
buf.write_u32(4, 67890);

let val = buf.read_u32(0);

buffer.free(buf);
```

**Use Cases**:
- Network protocol handling
- Binary data processing
- Crypto operations
- Image/video processing
- FFI interoperability

**How It Works**:
1. Buffer allocation API
2. Type-safe read/write operations
3. Bounds checking
4. Alignment guarantees
5. Memory lifecycle management

**Integration Points**:
- New module: Buffer manager
- Object model: Buffer type
- Evaluator: Buffer operations
- Security: Bounds checking

**Implementation Complexity**: Medium (4-5 days)

---

### 9. `simd` - Vector Operations

**Overview**:
SIMD (Single Instruction Multiple Data) vector operations for parallel computation.

**Syntax**:
```zexus
let a = simd.vector([1, 2, 3, 4]);
let b = simd.vector([5, 6, 7, 8]);

let c = simd.add(a, b);      // [6, 8, 10, 12]
let d = simd.multiply(a, b); // [5, 12, 21, 32]
let dot = simd.dot(a, b);    // 70
```

**Use Cases**:
- Image/video processing
- Machine learning
- Scientific computing
- Financial calculations
- Signal processing

**How It Works**:
1. SIMD vector type
2. Hardware-accelerated operations
3. Intrinsics mapping
4. Type-safe vector operations
5. Automatic optimization

**Integration Points**:
- New module: SIMD operations
- Type system: Vector types
- Compiler: SIMD instructions
- Optimizer: Vector code generation

**Implementation Complexity**: High (6-8 days)

---

## 🎯 Convenience Features (4)

### 10. `elif` - Else-If Conditionals 🚀 IN PROGRESS

**Overview**:
Standard `elif` (else-if) conditional branches instead of nested if-else chains.

**Syntax**:
```zexus
if x > 10 {
  print("large");
} elif x > 5 {
  print("medium");
} elif x > 0 {
  print("small");
} else {
  print("negative");
}
```

**Use Cases**:
- Multi-branch conditional logic
- State machines
- Control flow simplification
- Readability improvement

**How It Works**:
1. Add `ELIF` token to lexer
2. Extend parser to handle elif chains
3. Extend `IfExpression` AST node
4. Evaluator handles elif chain evaluation
5. Transpile to nested if-else if needed

**Current Status**: Using nested if-else internally? Need to check

**Integration Points**:
- Lexer: ELIF keyword
- Parser: elif clause handling
- AST: IfExpression.elif_branches
- Evaluator: elif evaluation logic

**Implementation Complexity**: Low (1-2 days)

---

### 11. `defer` - Cleanup Execution

**Overview**:
Guarantee code execution when scope exits (Go-like defer).

**Syntax**:
```zexus
fn process_file(path: string) {
  let file = open(path);
  defer file.close();  // Guaranteed to run
  
  // ... do work with file ...
  
}  // file.close() runs automatically here
```

**Use Cases**:
- Resource cleanup (files, connections, locks)
- Stack-based allocation
- Transaction cleanup
- Error handling

**How It Works**:
1. Track deferred statements
2. Store in scope stack
3. Execute in LIFO order on scope exit
4. Execute even on exception
5. Optimization for simple cases

**Integration Points**:
- Parser: defer keyword
- Evaluator: Defer stack
- Environment: Scope tracking
- Error handling: Exception cleanup

**Implementation Complexity**: Medium (3-4 days)

---

### 12. `pattern` - Pattern Matching

**Overview**:
Pattern matching for data destructuring and conditional logic (like Rust/Python).

**Syntax**:
```zexus
let result = [1, 2, 3];

pattern result {
  case [head, ...tail] => print(head);
  case [1, 2, x] => print(x);
  case empty => print("empty");
}

pattern user {
  case {name: "John", age: 30} => print("John");
  case {name: n, age: a} if a > 18 => print("Adult: " + n);
  default => print("Other");
}
```

**Use Cases**:
- Destructuring assignments
- Conditional logic
- Data extraction
- Type checking

**How It Works**:
1. Pattern syntax in parser
2. Pattern matching AST nodes
3. Unification algorithm
4. Guard expressions
5. Exhaustiveness checking

**Integration Points**:
- Parser: pattern syntax
- AST: PatternMatch node
- Evaluator: Unification logic
- Type checker: Exhaustiveness

**Implementation Complexity**: High (5-7 days)

---

## 📊 Advanced Features (3)

### 13. `enum` - Type-Safe Enumerations

**Overview**:
Type-safe enumerations with associated values (like Rust enums or TypeScript unions).

**Syntax**:
```zexus
enum Color {
  Red,
  Green,
  Blue
}

enum Result {
  Ok(value: any),
  Error(message: string)
}

let c = Color.Red;
let r = Result.Ok(42);

pattern r {
  case Result.Ok(v) => print("Success: " + v);
  case Result.Error(msg) => print("Error: " + msg);
}
```

**Use Cases**:
- Type-safe return values
- State representations
- Tagged unions
- Error handling without exceptions

**How It Works**:
1. Enum type definition
2. Variant support
3. Pattern matching integration
4. Type safety in pattern guards
5. Serialization support

**Integration Points**:
- Parser: enum syntax
- Type system: Enum types
- Evaluator: Enum construction
- Pattern matching: Enum variants

**Implementation Complexity**: Medium (4-6 days)

---

### 14. `stream` - Event Streaming

**Overview**:
Event-driven programming with streams (reactive programming).

**Syntax**:
```zexus
let numbers = stream.create([1, 2, 3, 4, 5]);

numbers
  .map(fn(x) { return x * 2; })
  .filter(fn(x) { return x > 5; })
  .subscribe(fn(x) {
    print("Event: " + x);
  });

// Can also handle async events
let events = stream.from_channel("user_events");
events.subscribe(fn(event) {
  print("User event: " + event.type);
});
```

**Use Cases**:
- Reactive programming
- Event handling
- Data transformations
- Async operations
- Real-time systems

**How It Works**:
1. Stream abstraction
2. Operator implementation (map, filter, etc.)
3. Subscription mechanism
4. Async support
5. Backpressure handling

**Integration Points**:
- New module: Stream library
- Evaluator: Async support
- Type system: Stream types
- Runtime: Event loop

**Implementation Complexity**: High (6-8 days)

---

### 15. `watch` - Reactive State

**Overview**:
Reactive state management with automatic dependency tracking (like Vue.js reactivity).

**Syntax**:
```zexus
let user = watch({
  name: "John",
  age: 30,
  email: "john@example.com"
});

watch user.name, fn() {
  print("Name changed to: " + user.name);
};

user.name = "Jane";  // Triggers watcher
```

**Use Cases**:
- UI state management
- Reactive frameworks
- Data binding
- Automatic updates
- Dependency tracking

**How It Works**:
1. Reactive object wrapper
2. Dependency tracking
3. Watcher registration
4. Change notifications
5. Computed properties

**Integration Points**:
- Object model: Reactive wrapper
- Parser: watch syntax
- Evaluator: Watch callbacks
- Type system: Reactive types

**Implementation Complexity**: High (6-8 days)

---

### 16. `sandbox` - Isolated Execution

**Overview**:
Execute untrusted code in an isolated sandbox with controlled permissions.

**Syntax**:
```zexus
let untrusted_code = `
  let x = 10;
  let y = 20;
  return x + y;
`;

let result = sandbox.execute(untrusted_code, {
  permissions: ["read", "compute"],
  timeout: 1000,
  memory_limit: 10_000_000
});
```

**Use Cases**:
- Plugin execution
- Untrusted scripts
- User-provided code
- Security isolation
- Resource limiting

**How It Works**:
1. Code isolation
2. Permission system
3. Resource limits (memory, CPU, time)
4. Capability-based security
5. Controlled API access

**Integration Points**:
- Parser: sandbox syntax
- Evaluator: Isolated execution
- Security: Permission checks
- Runtime: Resource management

**Implementation Complexity**: High (7-10 days)

---

## Summary Table

| # | Feature | Category | Status | Complexity | Days | Priority |
|---|---------|----------|--------|-----------|------|----------|
| 1 | seal | Security | ✅ Done | Low | 2 | P0 |
| 2 | const | Security | 🚀 IP | Low | 1 | P0 |
| 3 | audit | Security | 📋 Planned | Medium | 3 | P1 |
| 4 | restrict | Security | 📋 Planned | Medium | 4 | P1 |
| 5 | native | Performance | 📋 Planned | High | 8 | P2 |
| 6 | gc | Performance | 📋 Planned | Medium | 4 | P2 |
| 7 | inline | Performance | 📋 Planned | Medium | 5 | P2 |
| 8 | buffer | Performance | 📋 Planned | Medium | 4 | P2 |
| 9 | simd | Performance | 📋 Planned | High | 7 | P3 |
| 10 | elif | Convenience | 🚀 IP | Low | 1 | P0 |
| 11 | defer | Convenience | 📋 Planned | Medium | 3 | P1 |
| 12 | pattern | Convenience | 📋 Planned | High | 6 | P1 |
| 13 | enum | Advanced | 📋 Planned | Medium | 5 | P2 |
| 14 | stream | Advanced | 📋 Planned | High | 7 | P2 |
| 15 | watch | Advanced | 📋 Planned | High | 7 | P3 |
| 16 | sandbox | Advanced | 📋 Planned | High | 8 | P3 |
| | **TOTAL** | | | | **88 days** | |

**Legend**:
- ✅ Done - Fully implemented
- 🚀 IP - In Progress
- 📋 Planned - Queued for implementation
- P0 - Priority 0 (Critical path)
- P1 - Priority 1 (High value)
- P2 - Priority 2 (Medium value)
- P3 - Priority 3 (Nice to have)

---

**Next Steps**:
- Review IMPLEMENTATION_GUIDE.md for technical details
- Check CODE_EXAMPLES.md for working examples
- See ROADMAP.md for timeline and sequencing
