Enable Recursive Type Support In Bincode-ts

Hey guys, let's dive into a feature request to supercharge bincode-ts! This is all about supporting recursive types in your Rust-to-TypeScript data transfers. If you've ever wrestled with nested data structures like trees or linked lists, you'll understand the pain this aims to solve. Let's get into why this matters, how it could work, and why it's a game-changer for certain projects. This article will cover all the necessary details about the feature.

🚀 Feature Description: Seamless Recursive Type Handling

So, what are we actually talking about? The main goal is to make bincode-ts handle recursive Rust structs that use Box<T>. In Rust, this is a super common pattern to define types that refer to themselves, like a tree node that can have child nodes. Because Rust needs to know the size of everything at compile time, Box<T> lets you sidestep this by putting the recursive part on the heap, and giving a known size. We want bincode-ts to serialize and deserialize these structures flawlessly. This means taking a Rust struct with Box pointers, converting it into a binary format, and then, on the TypeScript side, turning that binary data back into a corresponding recursive type or interface.

Think about a binary tree, where each node can have left and right children, which are also nodes. Without Box<T>, you run into issues because the compiler doesn't know how big a node is because it contains other nodes. That's where Box comes in, by allocating space for the child nodes on the heap, the size is known at compile time. This feature would make it much easier to work with these kinds of structures, eliminating the need for awkward workarounds.

💡 Motivation: Solving Data Structure Frustration

Ever tried to move complex, nested data from Rust to TypeScript? You know the struggle. Currently, bincode-ts doesn't natively support these recursive types. This is frustrating because it limits the kinds of data you can easily transfer. If you're working on a project that involves trees, graphs, or any other hierarchical data, you're forced to either flatten your data structures or come up with your own custom serialization/deserialization logic. And honestly, that's a pain.

This is because the library needs to understand how to follow the Box pointers and reconstruct the structure on the receiving end. Imagine trying to serialize an Abstract Syntax Tree (AST) or a game scene graph. These are perfect examples of where recursive structures are essential. Without direct support in bincode-ts, you're stuck writing a lot of extra code, which is not only time-consuming but also introduces potential for errors. It's all about making your workflow smoother and more efficient, so you can focus on the core logic of your app instead of wrestling with serialization problems. By fixing this limitation, we unlock a world of possibilities for projects that rely on complex data structures.

🎯 Proposed Solution: How it Should Work

Here's the plan: bincode-ts needs to learn to love Box<T>. The serialization process should recognize the Box and then serialize the data inside the box, following the pointer to where the actual data is stored. This way, during deserialization, it can reconstruct the nested structure correctly on the TypeScript side. The main idea is to make the process seamless. You shouldn't have to think about it. The library should handle the pointer chasing for you, making the whole experience as easy as possible.

In terms of implementation, the library would need to be updated to understand how Box<T> works in Rust. When it encounters a Box<T> field, instead of trying to serialize the Box itself, it would serialize the value that the Box points to. On the TypeScript side, the deserialization would need to reconstruct this nested object hierarchy. This means creating the appropriate nested TypeScript types or interfaces that mirror the structure of the original Rust struct. So, when you get your data back in TypeScript, it's ready to use without any extra work. The goal is for developers to be able to define their recursive structs in Rust, serialize them, and have them automatically deserialize into a usable form in TypeScript.

🔄 Alternatives Considered: The Flattening Nightmare

The main alternative to direct support for recursive types is manual flattening. Basically, you'd have to convert your recursive data structure (like a tree) into a non-recursive structure (like a flat array or a map) before serialization. Then, on the TypeScript side, you'd have to write extra code to rebuild the original tree structure from this flat representation. This approach is not great, and here’s why.

First, it introduces a ton of boilerplate code on both the Rust and TypeScript sides. You'd need code to flatten the structure, serialize it, deserialize it, and then reconstruct it. It's a lot of extra work, which increases development time and complexity. Second, it can be error-prone. The more code you write, the more chances there are for bugs. Any mistake in the flattening or reconstruction logic could lead to incorrect data being passed between Rust and TypeScript. And finally, it's usually less efficient. Flattening and reconstructing data structures adds extra overhead, which can slow down your application. Direct support for recursive types avoids all this extra work and makes the whole process more efficient and less prone to errors.

📋 Implementation Details: Code Examples and Logic

Here's a more detailed look at how this could work under the hood. The key is to add support for Rust's smart pointers, particularly Box<T>. These pointers are essential for defining recursive data structures in Rust because they allow you to work with types of unknown size at compile time. bincode-ts needs to recognize Box<T> and serialize the contents of the box rather than the box itself. This is where the magic happens.

Here's a typical example of a recursive binary tree struct in Rust:

#[derive(Serialize, Deserialize)]
pub struct Node {
    pub value: String,
    pub left: Option<Box<Node>>,
    pub right: Option<Box<Node>>,
}

During serialization, bincode-ts should recognize the Box<Node> in the left and right fields and serialize the Node that the Box is pointing to. During deserialization on the TypeScript side, bincode-ts would create the corresponding TypeScript type or interface, recursively handling the nested structure. For instance, the TypeScript equivalent might look something like this:

interface Node {
  value: string;
  left: Node | null;
  right: Node | null;
}

The library would need to be smart enough to follow these pointers and reconstruct the nested object hierarchy, ensuring that the data is correctly represented in both Rust and TypeScript.

📝 Additional Context: Real-World Use Cases

Think about the applications that would benefit from this. Abstract Syntax Trees (ASTs) are a great example. ASTs are used in compilers and interpreters to represent the structure of code. They're inherently recursive. Being able to serialize and deserialize ASTs between Rust and TypeScript would be incredibly useful for tools like code editors, linters, and code analysis tools. Another use case is scene graphs in game development. Scene graphs are used to organize the objects and elements in a game world. They are also recursive, as objects can contain other objects. Enabling support for recursive types would make transferring scene graph data between Rust-based game engines and TypeScript-based frontends much easier. This feature would make bincode-ts a more powerful tool, enabling easier transfer of complex, nested data structures.

✅ Acceptance Criteria: Making it Happen

To make sure this feature is a success, here are some things that need to be checked off:

• Recursive Rust structs using Box<T> can be serialized without issues.
• The serialized data can be deserialized in TypeScript into a corresponding recursive type.
• Documentation needs to be updated with an example of a recursive Rust struct and its TypeScript equivalent.
• Tests should cover various recursive structures like linked lists and trees to ensure everything works as expected.
• The implementation should not significantly degrade the performance of non-recursive types.

By addressing these points, we can ensure that bincode-ts provides robust support for recursive data structures, making it even more useful for projects involving Rust and TypeScript.

For more information about the bincode-ts, you can visit the official repository.