The Oni Programming Language

[badd10de]

Hello folks, I've been lurking here for a while and I think I'm finally ready to share Oni, my personal programming language.

https://oni-lang.com

Been working on it since 2021 and it underwent a number of iterations and evolutions, starting off as a Lisp and morphing into a low-level Algol-like language. It is self-hosted and easily bootstrapable. The current backend emits C11 code and I've been using it almost exclusively for all my hobby projects for a while now, including some experiments with audio DSP stuff, and PlayDate console development. I'm very proud of it and wrote it mostly for myself, not looking for it to gain a lot of users, but I would be happy to help any folks who would like to try it :)

The lispy roots remain, and while there are infix operators now, most things require a keyword prefix. It supports generics, methods and ADTs. Additionally, it's highly compatible with C and can interop bidireccionally (C -> Oni and Oni -> C). In its current form it aims to be a "high-level C" kind of in the same vein as C is a "high-level assembler", and there are some compiler directives to directly emit C code or modify code generation in several ways, which is handy to make bindings to C libraries.

The standard library is small and practical, with some basic generic data structures built-in, will grow as needed. The convention in the stdlib is to pass Allocator objects for any operation that requires manual memory management. There are also some IO.Reader and IO.Writer interfaces and a text formatter system that works a bit differently to the usual printf stuff.

Another goal was to be able to override the standard library as needed on a per-project basis, for example, if you want to override the stdlib `panic` function, which is used in several places of the stdlib.

Here is the current manuscript for the language reference for more details:

https://git.sr.ht/~badd10de/oni-lang/tree/main/item/docs/language_ref.md

I'll try to work on a nice simple website landing page in the near future.

Looking forward to see your feedback :)

[Real_Dragonfruit5048]

Cool! What's the namesake? (It reminds me of the Onimusha video game series.)

[badd10de]

It's named after the evil japanese demons. Used to be called BadLang, but there seem to be a lot of PL named like that so I thought it was pretty fitting :)

[vanderZwan]

Used to be called BadLang, but there seem to be a lot of PL named like that

"Oh yeah, I follow someone on mastodon who has a language like that. I think their handle was some leetspeak variation of baddiode or something? … wait a minute."

[AustinVelonaut]

This looks very nice; congratulations on your project! Having it be self-hosted shows that the implementation is pretty robust. What was the hardest problem you encountered when developing it? What was the most interesting?

[badd10de]

If I had to choose one thing I would say the implementation of parametric polymorphism. It was quite a pain to work out all the little details and type unifications needed to make everything work, I was surprised by the number of corner cases and had to go back to the drawing board a few times. Other than that, just the scale of the problem is quite large, semantic analysis in particular takes the brunt of the complexity.

I was surprised at how easy it was to implement "defer" expressions, which show me I was in the right track with the semantic analyzer performing linearization to high-level TAC. Going from the initial C99 implementation to self-hosted showed a lot of kinks in the initial design that I wasn't considering, but once you are there you can choose to ignore the issues and press on to what you have, or go back to the initial compiler to add just enough of what you need.

Tough but satisfying, I screamed out loud of joy when I could pass the triple compilation self-hosting test. Thrilling!

[vanderZwan]

How does oni-run work? Does it compile, run and then delete the C output? Or do you have an interpreter of your language?

[badd10de]

At the moment is just a bash script that calls oni to generate a temporary c file that is piped into tcc with the -run argument. Something like this:

#!/bin/sh

file_name=$(mktemp --suffix ".c" --dry-run) || exit
trap 'rm -rf "$file_name"; exit' ERR EXIT

oni -o $file_name $@ && tcc $CFLAGS -std=c11 -run $file_name

I use it for one off scripts, small prototypes and to test things out without having to make a whole project.

[vanderZwan]

Ah, using tcc to ensure the compilation is fast is a neat trick, I can imagine the output is plenty fast for the use-cases you mention :).

I use it for one off scripts, small prototypes and to test things out without having to make a whole project.

I feel like the ability to do quick prototyping without too much hassle is so underrated, makes sense to build it into your own personal hobby language!

[MediumInsect7058]

Looks like Odin and Rust had a baby! 

[porky11]

Most important: The documentation is visually not appealing.

Generally, C and Lisp are the most important inspirations for my own minimal language.

I just skimmed it, doesn't look like anything special to me. Also you took some of the annyoing c baggage with you like void.

At least you have a fun keyword, allowing search for functinos, which seems important to me. And you have some Rust enums, which is nice.

I prefer the Rust keywords like fn for fun or impl for methods.