2025-10-01
Greetings, Nim community!
What it is: Nimony is a new compiler for a Nim variant aimed at becoming Nim 3.0 over time. The current focus is the Aufbruch mode: destructor-based memory management (ARC), value-centric semantics, predictable code generation, and a plugin-based metaprogramming model.
This is our first release, version 0.2, which provides a working core for basic programs. It’s an early preview, not a complete language, and targets developers interested in testing the fundamentals.
This time, I (planetis) was tasked with providing a review of the current state of Nimony as of 30 October 2025. We thought an honest opinion is better than a generic enthusiastic release announcement.
For this purpose, I wrote a simple UI program: in about 250 lines of…
2025-10-01
Greetings, Nim community!
What it is: Nimony is a new compiler for a Nim variant aimed at becoming Nim 3.0 over time. The current focus is the Aufbruch mode: destructor-based memory management (ARC), value-centric semantics, predictable code generation, and a plugin-based metaprogramming model.
This is our first release, version 0.2, which provides a working core for basic programs. It’s an early preview, not a complete language, and targets developers interested in testing the fundamentals.
This time, I (planetis) was tasked with providing a review of the current state of Nimony as of 30 October 2025. We thought an honest opinion is better than a generic enthusiastic release announcement.
For this purpose, I wrote a simple UI program: in about 250 lines of code, we have a Tic‑Tac‑Toe game with an AI running in a worker thread—showing what’s already possible. You can get it here. It uses the raylib library for graphics.
And indeed, quite a few modules from the standard library have already been ported, though some not in their entirety: tables, hashes, intsets, parseopt, paths, dirs, unicode, encodings, monotimes, locks, rawthreads, syncio, setutils, strutils, parseutils, envvars, cmdline, memfiles, math. Together they give you a well‑rounded set of functionality to start writing programs in Nimony.
Surprisingly, a lot of language features already work. For example, besides the usual imperative style most Nim programs follow, methods and dynamic polymorphism worked. I encountered a single compiler crash related to inheritance; ringabout fixed it the same day. This shows how eager the Nim compiler developers are to ship the next generation of Nim ASAP—so help them out by reporting bugs.
Nimony does seem to struggle with type resolution. “Error: type mismatch: got: X but wanted: Y” is the most common issue I encountered—sometimes X and Y are just auto or seq. By itself, this message doesn’t provide enough information beyond the line number. Nevertheless, it hasn’t blocked me from writing working Nimony programs.
Notably, case-insensitive identifiers are missing, which I noticed due to the odd capitalization of the AST node kinds (e.g., CallstrlitS, StaticstmtS). At this point, the debate doesn’t matter much to me—as long as I get my copy of “Learn Nim the HARD WAY” from Zed Shaw.
It’s also worth talking about my experience using AI chatbots while writing code. For my experiments, I needed to know what’s currently possible with Nimony, so I pasted Araq’s progress reports into GPT5‑high and got a table of what works. I used that as context to decide what to test next.
From all the experiments I made, certain templates and complex constants stood out as not working. For the latter, though, Nimony plugins seem to be a solid alternative, with a pleasant and minimalistic tree‑construction API.
When my code had errors, I took the opportunity to evaluate how different LLMs understand Nim, and they did well. Having the hyped “AI agents” understand Nim is important for adoption.
At that point, I concluded my testing. If I had more time, I’d try to create a minimal example for the ESP32—let’s keep that promise for the next release.
Overall, I think Nimony v0.2 is a bold step forward—building on solid ideas from Nim’s development and a new, interesting compiler architecture—and I hope it gains more traction. It certainly deserves it.
If you have time, try things out, report bugs, ask questions, and send PRs—every bit of feedback helps shape the direction.
Prebuilt packages (x86, arm64):
- Fedora: https://copr.fedorainfracloud.org/coprs/planetis/nim/builds/
- Ubuntu: https://launchpad.net/~planetis/+archive/ubuntu/nim/+packages
On other platforms, build and install Nimony from source:
Clone the repository:
git clone https://github.com/nim-lang/nimony.git
cd nimony
git checkout v0.2.0
Build using the hastur tool (requires an existing Nim installation):
nim c -r src/hastur build all
If your time is scarce but you want this direction to continue, contributions are welcome via our Open Collective: https://opencollective.com/nim.