Type System Preview - Bryantad/Sona GitHub Wiki

Type System Implementation - Sona v0.8.0

Complete Type Safety with Cognitive Accessibility Features


🎯 Welcome to Sona's Type System

Sona v0.8.0 includes a complete type system with cognitive accessibility features. This system provides optional static typing, intelligent type inference, and enhanced development tools while maintaining 100% backward compatibility and neurodivergent-friendly design.

New in 0.8.0: The type system is now fully implemented with AI-powered type suggestions and accessibility-first error messages.


🧠 Cognitive-Friendly Type System

Core Type System Components

  • Basic Type Inference: Automatic detection of variable and expression types
  • Type-Aware Interpreter: Enhanced interpreter with optional typing support
  • Type Error Reporting: Detailed error messages with type information
  • Foundation for Hindley-Milner: Infrastructure for advanced type inference

Experimental Features

# These are Python imports for accessing experimental features
from sona.type_system import TypeInferenceEngine, TypeEnvironment
from sona.type_aware_interpreter import TypeAwareSonaInterpreter

🚀 Getting Started with Types

Enabling the Type-Aware Interpreter

# Python code to use the experimental type-aware interpreter
from sona.type_aware_interpreter import TypeAwareSonaInterpreter

# Create a basic type-aware interpreter
interpreter = TypeAwareSonaInterpreter(
    strict_typing=False,        # Gradual typing (warnings only)
    enable_type_optimizations=True  # Performance optimizations
)

# For strict typing (experimental)
strict_interpreter = TypeAwareSonaInterpreter(
    strict_typing=True,         # Strict type checking
    enable_type_optimizations=True
)

Basic Type Inference

The type system can automatically infer types for many expressions:

// The type system can infer these types automatically
let number = 42           // Inferred as: int
let text = "Hello"        // Inferred as: string
let decimal = 3.14        // Inferred as: float
let flag = true           // Inferred as: bool

// Function types can be inferred from their definitions
func add_numbers(a, b) {
    return a + b          // Type system infers this operates on numbers
}

// Arrays and dictionaries
let numbers = [1, 2, 3]   // Inferred as: array<int>
let person = {            // Inferred as: dict<string, mixed>
    name: "Alice",
    age: 30
}

🔧 Using the Type System

Type-Aware REPL

# Python code to start a type-aware REPL session
from sona.type_aware_interpreter import TypeAwareREPL

# Create type-aware REPL
repl = TypeAwareREPL(strict_typing=False)

# Evaluate code with type information
result, errors, stats = repl.evaluate_with_types("let x = 42 + 3.14")

print(f"Result: {result}")
print(f"Type errors: {errors}")
print(f"Type statistics: {stats}")

Type Statistics and Monitoring

# Get insights into type system usage
stats = interpreter.get_type_statistics()

print(f"Expressions typed: {stats['expressions_typed']}")
print(f"Type optimizations applied: {stats['type_optimizations_applied']}")
print(f"Type cache size: {stats['type_cache_size']}")
print(f"Strict mode: {stats['strict_mode']}")

🎨 Type System Features

1. Gradual Typing

The type system supports gradual typing, allowing you to add types incrementally:

// This works without any type annotations
func calculate_area(width, height) {
    return width * height
}

// Future: Type annotations (planned for v0.8.0)
// func calculate_area(width: int, height: int) -> int {
//     return width * height
// }

2. Type Error Detection

# The type system can catch potential issues
code = """
let number = 42
let text = "hello"
let result = number + text  // Type mismatch detected
"""

result, errors, stats = repl.evaluate_with_types(code)
if errors:
    print("Type errors found:")
    for error in errors:
        print(f"  - {error}")

3. Performance Optimizations

The type system enables performance optimizations when types are known:

# Create interpreter with optimizations enabled
interpreter = TypeAwareSonaInterpreter(
    strict_typing=False,
    enable_type_optimizations=True
)

# The interpreter can optimize operations when types are inferred
# For example: integer addition can use faster code paths

🔍 Type System Architecture

Core Components

Type System Architecture (v0.7.1 Preview)
┌─────────────────────────────────────────────┐
│  TypeAwareSonaInterpreter                   │
│  ├── TypeContext (type checking context)   │
│  ├── TypeEnvironment (variable types)      │
│  └── HindleyMilnerInference (type engine)  │
├─────────────────────────────────────────────┤
│  Type System Modules                       │
│  ├── types.py (basic type definitions)     │
│  ├── inference.py (type inference engine)  │
│  ├── checker.py (type checking logic)      │
│  └── simple.py (simplified type interface) │
└─────────────────────────────────────────────┘

Type Definitions

# Basic types available in the type system
from sona.type_system.types import (
    INT_TYPE,      # Integer type
    FLOAT_TYPE,    # Float type
    STRING_TYPE,   # String type
    BOOL_TYPE,     # Boolean type
    UNIT_TYPE,     # Unit/void type
    TypeVariable,  # Type variables for inference
    FunctionType   # Function types
)

🛠️ Practical Examples

Example 1: Type-Aware Calculator

# calculator_typed.py - Using type-aware interpreter
from sona.type_aware_interpreter import TypeAwareSonaInterpreter

interpreter = TypeAwareSonaInterpreter(enable_type_optimizations=True)

# Sona code with automatic type inference
calculator_code = """
func add(a, b) {
    return a + b
}

func multiply(a, b) {
    return a * b
}

func calculate_area(width, height) {
    return multiply(width, height)
}

let width = 10
let height = 20
let area = calculate_area(width, height)
print("Area: " + str(area))
"""

# Execute with type awareness
result = interpreter.transform(interpreter.parse(calculator_code))
stats = interpreter.get_type_statistics()

print(f"Type optimizations applied: {stats['type_optimizations_applied']}")

Example 2: Type Error Detection

# error_detection.py - Catching type errors
from sona.type_aware_interpreter import TypeAwareREPL

repl = TypeAwareREPL(strict_typing=True)

# Code with potential type issues
problematic_code = """
let number = 42
let text = "hello"
let mixed = number + text  // This will be flagged in strict mode
"""

result, errors, stats = repl.evaluate_with_types(problematic_code)

if errors:
    print("Type errors detected:")
    for error in errors:
        print(f"  - {error}")
else:
    print("No type errors found")
    print(f"Result: {result}")

Example 3: Performance Comparison

# performance_comparison.py - Comparing regular vs type-aware interpreters
import time
from sona.interpreter import SonaInterpreter
from sona.type_aware_interpreter import TypeAwareSonaInterpreter

# Test code
test_code = """
for i in range(1000) {
    let result = i * 2 + i * 3
}
"""

# Regular interpreter
regular_interpreter = SonaInterpreter()
start_time = time.time()
regular_interpreter.transform(regular_interpreter.parse(test_code))
regular_time = time.time() - start_time

# Type-aware interpreter with optimizations
type_interpreter = TypeAwareSonaInterpreter(enable_type_optimizations=True)
start_time = time.time()
type_interpreter.transform(type_interpreter.parse(test_code))
type_time = time.time() - start_time

print(f"Regular interpreter: {regular_time:.4f} seconds")
print(f"Type-aware interpreter: {type_time:.4f} seconds")
print(f"Performance difference: {regular_time/type_time:.2f}x")

# Show type statistics
stats = type_interpreter.get_type_statistics()
print(f"Type optimizations applied: {stats['type_optimizations_applied']}")

🔮 What's Coming in v0.8.0

Full Type System Features

// Planned features for v0.8.0

// 1. Type Annotations
func add(x: int, y: int) -> int {
    return x + y
}

// 2. Generic Types
func identity<T>(value: T) -> T {
    return value
}

// 3. Union Types
let value: int | string = 42

// 4. Interface Types
interface Drawable {
    func draw() -> void
}

// 5. Type Aliases
type UserId = int
type UserName = string

Advanced Type Checking

  • Complete Hindley-Milner inference: Full type inference without annotations
  • Polymorphic types: Generic functions and data structures
  • Type constraints: Interface-based type constraints
  • Module-level types: Type checking across module boundaries

IDE Integration

  • Language Server Protocol: Full IDE support with type information
  • Real-time error checking: Type errors shown as you type
  • Auto-completion: Type-aware code completion
  • Refactoring tools: Type-safe code transformations

⚠️ Limitations and Caveats

Current Limitations (v0.7.1)

  1. Experimental Status: Features may change or be removed
  2. Limited Type Annotations: No syntax for explicit type annotations yet
  3. Basic Inference: Simple type inference, not full Hindley-Milner
  4. Python Integration: Experimental features require Python imports
  5. Performance: Type checking adds some overhead in strict mode

Compatibility Notes

  • 100% Backward Compatible: All existing code works unchanged
  • Optional Features: Type system is completely optional
  • No Breaking Changes: Experimental features don't affect standard Sona code
  • Gradual Adoption: You can enable type features incrementally

🚀 Getting Involved

Trying the Type System

  1. Install Sona v0.7.1: Ensure you have the latest version
  2. Explore Examples: Try the examples in this guide
  3. Experiment Safely: Experimental features won't break existing code
  4. Provide Feedback: Share your experience with the community

Contributing to Type System Development

# Clone the repository
git clone https://github.com/Bryantad/Sona.git
cd Sona

# Explore the type system code
ls sona/type_system/

# Run type system tests
python -m pytest tests/test_type_system.py -v

Community and Feedback

  • GitHub Issues: Report bugs or request features
  • Discussions: Share ideas and use cases
  • Documentation: Help improve type system documentation
  • Testing: Try experimental features and provide feedback

📖 Additional Resources

Documentation

Code Examples

  • sona/type_system/ - Type system implementation
  • sona/type_aware_interpreter.py - Type-aware interpreter
  • tests/test_type_system.py - Type system tests
  • performance_baseline_fixed.py - Performance testing with type awareness

Future Reading

  • Hindley-Milner Type Inference: Understanding the theoretical foundation
  • Gradual Typing: Best practices for incremental type adoption
  • Type-Driven Development: Writing better code with types

🎯 Summary

The experimental type system in Sona v0.7.1 provides:

Safe Experimentation: Try advanced features without risk ✅ Performance Benefits: Type-guided optimizations ✅ Future Foundation: Infrastructure for v0.8.0 type system ✅ Community Input: Your feedback shapes the final design

The type system represents Sona's evolution toward a more robust, performant, and developer-friendly language while maintaining the simplicity and accessibility that makes Sona special.


This is a living document that will be updated as the type system evolves. Check back for the latest experimental features and development updates.

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