I'm making a dynamic language in Rust
An implementation of a dynamic programming language in Rust. Includes: Parser/Compiler, REPL, Virtual Machine, Bytecode Disassembler This started out as a learning project to teach myself Rust. It has grown into a decently substantial piece of software and I've learned quite a bit in the process! Some neat things: + A garbage collector that can store dynamically sized types without any double-indirection (i.e. I have my own Box implementation with manual alloc/dealloc) + The smart pointer used to reference GCed data is a thin pointer. The ptr metadata needed for DSTs is stored in…
In plain words
This is a dynamic programming language implemented in Rust, featuring a parser, compiler, REPL, virtual machine, and bytecode disassembler. It is designed for developers interested in language implementation and systems programming. The project stands out for its custom garbage collector that handles dynamically sized types efficiently through thin pointers and manual memory management, supporting weak references while keeping core values compact at 16 bytes.
written from the facts on this page · September 2026
From the sources
In the maker’s words, at launch
An implementation of a dynamic programming language in Rust. Includes: Parser/Compiler, REPL, Virtual Machine, Bytecode Disassembler This started out as a learning project to teach myself Rust. It has grown into a decently substantial piece of software and I've learned quite a bit in the process! Some neat things: + A garbage collector that can store dynamically sized types without any double-indirection (i.e. I have my own Box implementation with manual alloc/dealloc) + The smart pointer used to reference GCed data is a thin pointer. The ptr metadata needed for DSTs is stored in the GC allocation itself, so that the GC smart pointer is just a single usize wide. This allows me to keep the core value enum Variant down to 16 bytes (8 bytes for data, the enum discriminant, and some padding). + The GC also supports weak references! + Statically dispatched type object model using a newtype wrapper and Rust's declarative macros. Ok, what that means is that I have a MetaObject trait that I can use to easily add new data types and define the behavior for specific types. Similar idea to Python's PyTypeObject though very different in implementation. However, I don't resort to dynamic dispatch or trait objects despite working with dynamically type data. Instead, I have a newtype wrapper over the core value enum Variant that statically dispatches to each of the enum branches! And then a few macros that minimize the boilerplate required if I want to add a new branch to Variant or a new method to MetaObject (just a single line in each case). + Different string representations! This was inspired by the flexstr crate. Strings that are short enough to fit inside a Variant are "inlined" directly in the value. Longer strings are either GCed or interned in a thread-local string table. All identifiers are interned. + An efficient implementation of closures inspired by Lua's upvalues. The language is still pretty WIP. I'm planning to add an import system, a small standard library, and a few other things (Yes, the name might not be the best, being also used by a well-known ReST docs generator, I'll take suggestions. I do like the name though, both as a reference to the mythological creature and the cat :D)
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