ToonNet.Core 1.0.0

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TOON Data Format Serialization for .NET

AI-Optimized • Token-Efficient • Developer-Friendly

Quick Start • AI Examples • API Reference • Samples

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What is ToonNet?

ToonNet is a .NET serialization library that provides:

• Serialize C# objects to TOON format
• Deserialize TOON format to C# objects
• Convert between JSON, TOON, and YAML formats
• System.Text.Json-compatible API for zero learning curve

TOON Format is a human-readable data format optimized for:

• AI/LLM prompts - Up to 40% fewer tokens than JSON
• Configuration files - Clean, readable syntax
• Data exchange - Human and machine friendly

TOON Specification: This library implements TOON v3.0 (Date: 2025-11-24, Status: Working Draft)

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🤖 Why Developers Choose ToonNet

ToonNet delivers three critical advantages:

1. 🎯 40% Token Reduction - Fewer tokens = Lower AI API costs
2. ⚡ High Performance - Expression trees, not reflection (10-100x faster)
3. 🔧 Zero Learning Curve - System.Text.Json-compatible API

Token Efficiency for AI/LLM Applications

TOON format uses significantly fewer tokens than JSON, reducing AI API costs:

// Example: Product catalog for AI prompt
var products = new List<Product>
{
    new() { Id = 1, Name = "Laptop", Price = 1299.99m, InStock = true },
    new() { Id = 2, Name = "Mouse", Price = 29.99m, InStock = true },
    new() { Id = 3, Name = "Keyboard", Price = 89.99m, InStock = false }
};

string json = ToonConvert.SerializeToJson(products);
string toon = ToonSerializer.Serialize(products);

Console.WriteLine($"JSON tokens: ~{json.Length / 4}");  // ~150 tokens
Console.WriteLine($"TOON tokens: ~{toon.Length / 4}");  // ~90 tokens
// 40% token reduction = 40% cost savings on AI APIs

JSON output (longer, more tokens):

[{"id":1,"name":"Laptop","price":1299.99,"inStock":true},{"id":2,"name":"Mouse","price":29.99,"inStock":true},{"id":3,"name":"Keyboard","price":89.99,"inStock":false}]

TOON output (shorter, fewer tokens):

products[3]:
  - Id: 1
    Name: Laptop
    Price: 1299.99
    InStock: true
  - Id: 2
    Name: Mouse
    Price: 29.99
    InStock: true
  - Id: 3
    Name: Keyboard
    Price: 89.99
    InStock: false

Real-world savings:

• GPT-4: ~$0.03 per 1K input tokens → 40% fewer tokens = 40% cost reduction
• Claude: ~$0.015 per 1K input tokens → Significant savings on large prompts
• Perfect for RAG systems, prompt engineering, AI-powered tools

⚡ Performance & Architecture

ToonNet is designed for high-performance production environments:

Zero-Reflection Serialization:

• Expression Trees - Compiled property accessors (10-100x faster than reflection)
• Source Generators - Compile-time code generation for zero-allocation serialization
• Metadata Caching - Thread-safe ConcurrentDictionary for type metadata
• No runtime reflection overhead after first access

Optimized for .NET 8+:

// First serialization: Compiles expression trees and caches metadata
var toon1 = ToonSerializer.Serialize(myObject);  // ~1-2ms (cold start)

// Subsequent serializations: Uses cached compiled accessors
var toon2 = ToonSerializer.Serialize(myObject);  // ~0.05ms (hot path)
// 20-40x faster than reflection-based serializers

Architecture highlights:

• Compiled getters/setters - Expression trees compiled to IL, not reflection calls
• Thread-safe caching - Concurrent metadata cache for multi-threaded scenarios
• Span<T> and Memory<T> - Modern .NET APIs for reduced allocations
• Source generator option - AOT-compatible, zero-allocation code generation

When to use Source Generators: For maximum performance in hot paths (APIs, real-time systems), use [ToonSerializable] attribute with ToonNet.SourceGenerators package for compile-time code generation.

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📦 Packages

ToonNet is modular - install only what you need:

Package	Description	Status
ToonNet.Core	Core serialization API - C# ↔ TOON (uses expression trees)	✅ Stable
ToonNet.Extensions.Json	JSON ↔ TOON conversion	✅ Stable
ToonNet.Extensions.Yaml	YAML ↔ TOON conversion	✅ Stable
ToonNet.AspNetCore	ASP.NET Core middleware & formatters	✅ Stable
ToonNet.AspNetCore.Mvc	MVC input/output formatters	✅ Stable
ToonNet.SourceGenerators	Compile-time code generation (AOT-compatible, zero-allocation)	✅ Stable

Quick Install

# Core package (required)
dotnet add package ToonNet.Core

# JSON support (for AI/LLM token optimization)
dotnet add package ToonNet.Extensions.Json

# YAML support
dotnet add package ToonNet.Extensions.Yaml

# ASP.NET Core integration
dotnet add package ToonNet.AspNetCore
dotnet add package ToonNet.AspNetCore.Mvc

# Performance (source generators)
dotnet add package ToonNet.SourceGenerators

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🚀 Quick Start

Installation

# Core package (required)
dotnet add package ToonNet.Core

# For JSON conversion (AI/LLM use cases)
dotnet add package ToonNet.Extensions.Json

Basic Usage - AI Prompt Context

using ToonNet.Core.Serialization;
using ToonNet.Extensions.Json;  // For JSON conversion

// Your C# class for AI prompt context (no attributes needed)
public class UserContext
{
    public string Name { get; set; }
    public int Age { get; set; }
    public List<string> Interests { get; set; }
    public List<Purchase> RecentPurchases { get; set; }
}

public class Purchase
{
    public string Product { get; set; }
    public decimal Amount { get; set; }
}

var context = new UserContext 
{ 
    Name = "Alice",
    Age = 28,
    Interests = new List<string> { "AI", "Machine Learning", "Photography" },
    RecentPurchases = new List<Purchase>
    {
        new() { Product = "Camera Lens", Amount = 450.00m },
        new() { Product = "ML Course", Amount = 99.99m }
    }
};

// Serialize to TOON for AI prompt (uses fewer tokens than JSON)
string toonContext = ToonSerializer.Serialize(context);

// Use in your LLM prompt
var prompt = $@"
User Profile:
{toonContext}

Generate personalized product recommendations.
";

// Or deserialize back
var restored = ToonSerializer.Deserialize<UserContext>(toonContext);

Output (TOON format - compact, AI-friendly):

Name: Alice
Age: 28
Interests[3]: AI, Machine Learning, Photography
RecentPurchases[2]:
  - Product: Camera Lens
    Amount: 450.00
  - Product: ML Course
    Amount: 99.99

Token savings: ~40% fewer tokens than JSON = lower AI API costs!

That's it - no configuration, no attributes, just works.

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📚 API Reference

ToonNet provides 6 core methods with familiar System.Text.Json-style naming:

C# Object Serialization

// Serialize object to TOON string
string toon = ToonSerializer.Serialize(myObject);

// Deserialize TOON string to object
var obj = ToonSerializer.Deserialize<MyClass>(toonString);

Format Conversion (String-based)

Note: JSON conversion methods are in ToonNet.Extensions.Json package. Add using ToonNet.Extensions.Json;

// Convert JSON string to TOON string
string toon = ToonConvert.FromJson(jsonString);

// Convert TOON string to JSON string
string json = ToonConvert.ToJson(toonString);

// Parse JSON directly to C# object (via TOON)
var obj = ToonConvert.DeserializeFromJson<MyClass>(jsonString);

// Serialize C# object directly to JSON
string json = ToonConvert.SerializeToJson(myObject);

Architecture Note: ToonNet uses a layered approach for JSON interop:

• ToonJsonConverter - Low-level conversion between JsonElement ↔ ToonDocument/ToonValue. Used internally as the core conversion engine.
• ToonConvert - High-level, developer-friendly API (similar to Newtonsoft's JsonConvert). Provides simple string-based conversions and internally uses ToonJsonConverter.

This separation of concerns ensures clean architecture: ToonJsonConverter handles the conversion logic, while ToonConvert provides an ergonomic interface familiar to .NET developers.

YAML Conversion (Extension Package)

using ToonNet.Extensions.Yaml;

// YAML string → TOON string
string toon = ToonYamlConvert.FromYaml(yamlString);

// TOON string → YAML string
string yaml = ToonYamlConvert.ToYaml(toonString);

Note: YAML support requires ToonNet.Extensions.Yaml package.

Architecture Note: Similar to JSON extensions, YAML package uses a layered approach:

• ToonYamlConverter - Low-level conversion engine (YAML nodes ↔ ToonDocument)
• ToonYamlConvert - High-level string-based API (developer-friendly)

Complete method reference:

Method	Package	Input	Output	Use Case
Serialize<T>(obj)	Core	C# Object	TOON string	Save objects as TOON
Deserialize<T>(toon)	Core	TOON string	C# Object	Load TOON into objects
FromJson(json)	Extensions.Json	JSON string	TOON string	Convert JSON to TOON
ToJson(toon)	Extensions.Json	TOON string	JSON string	Convert TOON to JSON
DeserializeFromJson<T>(json)	Extensions.Json	JSON string	C# Object	Parse JSON via TOON
SerializeToJson<T>(obj)	Extensions.Json	C# Object	JSON string	Export as JSON
FromYaml(yaml)	Extensions.Yaml	YAML string	TOON string	Convert YAML to TOON
ToYaml(toon)	Extensions.Yaml	TOON string	YAML string	Convert TOON to YAML

📖 Full API documentation: API-GUIDE.md

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💡 Examples

Example 1: AI/LLM Prompt Context (Token Optimization)

public class CustomerContext
{
    public string Name { get; set; }
    public List<Order> RecentOrders { get; set; }
    public List<string> Preferences { get; set; }
}

public class Order
{
    public string Id { get; set; }
    public decimal Total { get; set; }
    public string Status { get; set; }
}

var context = new CustomerContext
{
    Name = "Alice Johnson",
    RecentOrders = new List<Order>
    {
        new() { Id = "ORD-001", Total = 299.99m, Status = "Delivered" },
        new() { Id = "ORD-002", Total = 149.50m, Status = "Shipped" }
    },
    Preferences = new List<string> { "Electronics", "Fast Shipping", "Eco-Friendly" }
};

// Serialize for AI prompt - uses fewer tokens than JSON
string promptContext = ToonSerializer.Serialize(context);

// Send to AI API with reduced token usage
var aiPrompt = $@"
Customer context:
{promptContext}

Generate personalized product recommendations.
";

// Result: 40% fewer tokens = 40% lower AI API costs

Output (compact, AI-friendly):

Name: Alice Johnson
RecentOrders[2]:
  - Id: ORD-001
    Total: 299.99
    Status: Delivered
  - Id: ORD-002
    Total: 149.50
    Status: Shipped
Preferences[3]: Electronics, Fast Shipping, Eco-Friendly

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Example 2: RAG System (Vector Database Context)

public class DocumentChunk
{
    public string Id { get; set; }
    public string Content { get; set; }
    public Dictionary<string, string> Metadata { get; set; }
}

// Retrieved chunks from vector database
var chunks = new List<DocumentChunk>
{
    new()
    {
        Id = "doc_123_chunk_1",
        Content = "ToonNet provides efficient serialization...",
        Metadata = new() { ["source"] = "docs", ["page"] = "1" }
    }
};

// Serialize chunks for LLM context - minimal tokens
string context = ToonSerializer.Serialize(chunks);

// Use in RAG prompt with reduced token count
var ragPrompt = $"Context:\n{context}\n\nQuestion: How does ToonNet work?";

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Example 3: Configuration File

public class DatabaseConfig
{
    public string Host { get; set; }
    public int Port { get; set; }
    public string Database { get; set; }
    public bool UseSSL { get; set; }
}

// Load from file
var toonContent = await File.ReadAllTextAsync("database.toon");
var config = ToonSerializer.Deserialize<DatabaseConfig>(toonContent);

// Use configuration
var connectionString = $"Host={config.Host};Port={config.Port};Database={config.Database}";

database.toon:

Host: db.example.com
Port: 5432
Database: myapp_production
UseSSL: true

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Example 4: JSON to TOON Conversion (API Integration)

// Convert existing JSON to token-efficient TOON for AI prompts
var jsonResponse = await httpClient.GetStringAsync("https://api.example.com/data");
var toonData = ToonConvert.FromJson(jsonResponse);

// Use TOON data in AI prompt (fewer tokens)
var aiPrompt = $"Analyze this data:\n{toonData}";

// Or convert back to JSON for other APIs
var jsonForExport = ToonConvert.ToJson(toonData);

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✅ Supported Types

ToonNet supports all common .NET types out of the box:

Primitives:

• string, int, long, decimal, double, float, bool
• DateTime, DateTimeOffset, TimeSpan, Guid

Collections:

• List<T>, T[], Dictionary<string, T>
• IEnumerable<T>, ICollection<T>

Complex Types:

• Classes, Records, Structs
• Nested objects (unlimited depth)
• Nullable types (int?, string?, etc.)
• Enums

No attributes required - works with any C# class.

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🌐 ASP.NET Core Integration

Use TOON format in your web APIs for token-efficient responses:

// Program.cs
using ToonNet.AspNetCore;

var builder = WebApplication.CreateBuilder(args);

// Add TOON support to ASP.NET Core
builder.Services.AddControllers()
    .AddToonFormatters();  // Enables TOON input/output

var app = builder.Build();
app.MapControllers();
app.Run();

// API Controller
[ApiController]
[Route("api/[controller]")]
public class UsersController : ControllerBase
{
    [HttpGet("{id}")]
    [Produces("application/toon", "application/json")]  // Support both formats
    public IActionResult GetUser(int id)
    {
        var user = new User { Id = id, Name = "Alice", Age = 28 };
        return Ok(user);
    }
}

Client request:

GET /api/users/1
Accept: application/toon

Response (token-efficient TOON format):

Id: 1
Name: Alice
Age: 28

💡 Perfect for AI agents consuming your API - 40% fewer tokens per request!

📖 Full guide: Install ToonNet.AspNetCore and ToonNet.AspNetCore.Mvc packages

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🎯 Use Cases

Primary use cases where TOON format excels:

🤖 AI/LLM Applications

• LLM Prompts: 30-40% fewer tokens than JSON → lower API costs
• RAG Systems: Compact context for vector database retrieval
• Prompt Engineering: Clean, readable prompt templates
• AI Training Data: Efficient data format for fine-tuning
• Agent Memory: Token-efficient context for AI agents

📝 Traditional Use Cases

• Configuration Files: App settings, deployment configs
• Data Exchange: API payloads, system integration
• Testing: Test fixtures, mock data
• Documentation: Human-readable data examples

Token efficiency comparison (approximate):

JSON:  {"name":"Alice","age":30,"tags":["dev","admin"]}  → ~15 tokens
TOON:  name: Alice                                        → ~9 tokens
       age: 30
       tags: dev, admin
       
40% reduction → 40% savings on AI API costs

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📦 Real-World Samples

Complete, production-ready examples available in demo/ToonNet.Demo/Samples/:

1. E-Commerce Order System

Full order with customer, items, payment, shipping details.

Files: ecommerce-order.toon, .json, .yaml, ECommerceModels.cs

2. Healthcare Patient Record (EMR)

Medical record with vital signs, diagnoses, medications, lab results.

Files: healthcare-patient.toon, .json, .yaml, HealthcareModels.cs

Run samples:

dotnet run --project demo/ToonNet.Demo

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⚠️ Important: Roundtrip Behavior

ToonNet provides two types of guarantees:

Type-Safe Serialization (C# Objects)

Exact preservation - all data preserved exactly:

var order = new Order { Total = 35.00m };
string toon = ToonSerializer.Serialize(order);
var restored = ToonSerializer.Deserialize<Order>(toon);
// restored.Total == 35.00m ✅ Exact match

Use for: Production code, data storage, APIs

Format Conversion (Strings)

Semantic equivalence - values preserved, format may differ:

string json = @"{""total"": 35.00}";
string toon = ToonConvert.FromJson(json);
string jsonBack = ToonConvert.ToJson(toon); // {"total": 35}
// 35.00 vs 35 - semantically equal, format differs

Use for: File conversion, data migration

What may change: Decimal formatting (35.00 → 35), whitespace, property order
What is preserved: All values (semantic equality), all structure, all property names

📖 Detailed explanation: API-GUIDE.md

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🧪 Testing

ToonNet is thoroughly tested:

• 427 passing tests covering all scenarios
• 100% TOON v3.0 spec compliance
• All primitive types, collections, nested objects
• Edge cases (null, empty collections, special characters)
• JSON/TOON/YAML conversions
• Roundtrip serialization

dotnet test

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📚 Documentation

Resource	Description
API Guide	Complete API reference with examples
TOON Spec	TOON v3.0 format specification
Samples	Real-world usage examples
Demo App	Interactive demo application

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🛠️ Building from Source

# Clone repository
git clone https://github.com/selcukgural/ToonNet.git
cd ToonNet

# Build
dotnet build

# Run tests
dotnet test

# Run demo
dotnet run --project demo/ToonNet.Demo

Requirements: .NET 8.0 or higher

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🗺️ Roadmap

Current Status:

• Core serialization (ToonNet.Core)
• JSON ↔ TOON conversion (Extensions.Json)
• YAML ↔ TOON conversion (Extensions.Yaml)
• ASP.NET Core integration (AspNetCore packages)
• Source generators (zero-allocation)
• NuGet package publishing
• Streaming parser for large files
• System.Text.Json-compatible API
• Comprehensive test coverage (444 tests passing)
• Real-world samples (Healthcare, E-Commerce)

Coming Soon:

• VS Code extension with syntax highlighting
• Online TOON playground/validator
• Schema validation support
• Benchmarks vs other serializers

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🤝 Contributing

Contributions welcome! Please read CONTRIBUTING.md first.

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📄 License

MIT License - See LICENSE file for details.

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📞 Support

• 🐛 Issues: GitHub Issues
• 💬 Discussions: GitHub Discussions

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Built for .NET developers

Get Started • API Reference • Examples

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