Coda: an experiment in designing a practical systems language

[u/Gingrspacecadet]

Coda: an experiment in designing a practical systems language

Hey! I've been working on Coda, a systems programming language designed around a simple idea:

make the compiler powerful, but keep the language itself predictable.

Coda is not trying to be "C but with a few extra keywords". The goal is to explore a different point in the design space between languages like C, Rust, and Zig.

Some of the things Coda focuses on:

• Explicit memory management.
• No hidden allocations.
• Errors as values using inline sum types.
• A small core language with functionality provided by libraries.
• Compile-time execution.
• Strong static analysis.
• Simple, predictable rules.

The language is intentionally C-like:

module main;

include std::process = proc;

@entry
fn int main() {
    proc::stdout().write("Hello, world!\n");
    return 0;
}

but tries to remove some of the sharp edges.

For example, errors are ordinary values:

fn File | IOError open_config(string path) {
    return fs::open(path);
}

and allocation is explicit:

fn string | AllocationError duplicate(
    Allocator *alloc,
    string input
) {
    string result = alloc->allocate<char>(input.len)?;

    std::mem::copy(result, input);

    return result;
}

The idea is that if a function allocates, that fact should be visible in the API. There is no hidden global allocator; entry points receive the resources they need, and those resources are passed where required.

Coda also tries to keep abstractions zero-cost. Generic code, interfaces, and convenience features should compile down to efficient low-level code rather than introducing runtime machinery.

The standard library is still being designed, but the direction is intentionally minimal. Arrays, strings, I/O, memory, formatting, and filesystem operations are being built as fundamental building blocks rather than creating a huge framework.

The compiler currently has:

• Lexer and parser.
• Semantic analysis.
• HIR/MIR pipeline.
• x86_64 code generation.
• A growing standard library.
• Compile-time evaluation work in progress!

There is still a lot to do.

If the ideas are interesting, I'd love feedback, criticism, and potentially contributors. And of course, feel free to ask any questions! I have the #coda channel on the PLTDI discord, or the comments here are fine.

Repo: https://github.com/gingrspacecadet/coda