For the last few weeks I've been working on a "secret" project. I'm doing a best effort port of quickjs from C into Rust. Why? A few reasons:

• the author of quickjs is obviously a very talented programmer, and I hope to learn a lot going over the code
• to learn Rust better
• to learn the spec of Javascript better

I decided to go about it in a very mechanical way, straight translation of C to Rust, starting with the header file, then working from top to bottom. Most of the first ~2000 lines have just been translating structs, but I have had to make some interesting choices. I'll be detailing them in later posts, but here's a brief list:

• JSValue in QuickJS is a tagged enum stored as a 64bit int. I decided I can use a regular Rust enum
• Choosing whether pointer types are Option<T>, &T, or Rc<T>
• Deciding what to do with the various void *
• How to translate the "X-macro" idiom from C
• How to represent the GC layer.

The last one is what I'm currently working through. In qjs each gc-able object is part of a linked list and so contains a "klist" style entry (a prev and next node pointer). I believe that I could copy the direct implementation into rust, using the associated pointer arithmatic, but I also believe that it would be unidiomatic.

I'll follow up with more details in later posts