Roc ASCII · show and tell · Zulip Chat Archive

Most of the time it's best to support UTF-8, but sometimes you have data that is just ASCII and you can avoid some of the complexity of UTF-8, so I made a quick package with two types: an ASCII string and an ASCII character. See the docs for more info: https://hasnep.github.io/roc-ascii

Hannes (Feb 03 2025 at 12:10):

I've just released v0.3.0 of roc-ascii which supports Roc v0.0.0-alpha2 and changes the Ascii type from an opaque type to a plain List Char :)

Hannes (Aug 18 2026 at 02:37):

I've just released ~~v0.4.0~~ v0.4.1 of roc-ascii which supports the new Roc compiler :)

Aurélien Geron (Aug 18 2026 at 03:37):

Awesome @Hannes ! I'll add it to the list of libraries available in the Exercism Roc track, since most exercises that manipulate text assume it's ASCII-only. However, it looks like there's currently no release file (.tar.zst)?

Hannes (Aug 18 2026 at 04:46):

Hannes (Aug 18 2026 at 06:01):

Aurélien Geron (Aug 18 2026 at 06:30):

── ✗ package download failed ───────────────────────────────────────────────────────────────────────────────────────────

Failed to download and extract this package:

    https://github.com/Hasnep/roc-ascii/releases/download/v0.4.1/AnawhDawcVySaW3ywcvfUPuhbXfJK7jcwEHaMBAfVv2y.tar.zst

Error: FileNotFound.

── 1 error and 0 warnings ──────────────────────────────────────────────────────────────── bin/download-dependencies.roc

Hannes (Aug 18 2026 at 06:32):

Aurélien Geron (Aug 18 2026 at 06:32):

Oh it looks like the roc bundle command was launched from the root directory instead of inside the src directory:

% tar xvf AnawhDawcVySaW3ywcvfUPuhbXfJK7jcwEHaMBAfVv2y.tar.zst
x src/main.roc
x src/Char.roc
x src/Utils.roc
x src/Ascii.roc

Hannes (Aug 18 2026 at 06:46):

Luke Boswell (Aug 18 2026 at 06:47):

I think this is by design, you need to explicitly pass the files you want bundled. It doesn't auto find them like the old compiler

Luke Boswell (Aug 18 2026 at 06:48):

The design for packages and the targets is a little different. The goal is to give platform/package authors more flexibility and control.

Aurélien Geron (Aug 18 2026 at 06:49):

FYI, I just ran roc bundle main.roc inside the src directory, and the bundle contains all *.roc files in this directory (presumably because they're listed in main.roc).

Luke Boswell (Aug 18 2026 at 06:53):

Richard Feldman (Aug 18 2026 at 12:16):

Richard Feldman (Aug 18 2026 at 12:17):

like if you include a .roc file which imports other files, we should bring all those in so your bundle isn't broken :sweat_smile:

Hannes (Sep 04 2026 at 15:16):

Just released v0.5.0 which is compatible with the latest Roc nightly and has a functioning release URL you can use. Thanks to @Aurélien Geron for your help!

Hannes (Sep 04 2026 at 15:35):

app [main!] {
    cli: platform "https://github.com/roc-lang/basic-cli/releases/download/0.21.0/4rAQg8kUYZ3Vksr4qMQHpaFYNiHSn9GgS7gVxghd1XYV.tar.zst",
    ascii: "https://github.com/Hasnep/roc-ascii/releases/download/v0.5.0/5WxqRf15XVko4HxVq5dW8r84s95CxrtvzrjZYwbg9Z3H.tar.zst",
}

import cli.Stdout
import cli.Stderr
import cli.Stdin
import ascii.Ascii

repeat_input_but_shouting! = || {
    stdin = Stdin.read_to_end!().map_err(|_| "Failed to read from stdin!")?
    msg = Ascii.from_ascii_bytes(stdin).map_err(|_| "Non-ASCII input data!")?
    Stdout.write!(msg.to_uppercase().to_str()).map_err(|_| "Failed to write to stdout!")
}

main! = |_| {
    match repeat_input_but_shouting!() {
        Ok(_) => Ok({})
        Err(err_msg) => {
            _ = Stderr.line!(err_msg)
            Err(Exit(1))
        }
    }
}

❱ echo hi | roc example.roc
HI

Steve Howell (Oct 28 2026 at 19:35):

Before I realized/remembered that https://github.com/Hasnep/roc-ascii was a thing, I had Claude writing some code, and the same needs came up: is_digit, is_hex_digit, is_alphanumeric, is_whitespace, is_punctuation, is_control, is_letter, to_lowercase, to_uppercase are all in my codebase.

We actually differ on is_whitespace. My version is C's six bytes, which Zig and Go share.

Steve Howell (Oct 28 2026 at 19:40):

I think there's an argument to upstream some of these to the Roc standard library. OTOH there's a clear argument that individual developers can knock these out pretty easily. So I'm just giving a data point here.

Steve Howell (Oct 28 2026 at 20:49):

Steve Howell (Oct 29 2026 at 13:37):

I'm now using my ascii library in two different places, which makes me lean more toward wanting them as builtins eventually. It's not a true blocker for me, to be clear. But I'm from the Python school that "batteries included" is a good philosophy, and ascii helpers feel like batteries.

Anton (Oct 29 2026 at 14:15):

Richard Feldman (Oct 29 2026 at 16:06):

yeah I want to revisit after 0.1 - I don't really want to add design work projects to 0.1.0's scope unless they're really small and/or urgent :smile:

Steve Howell (Oct 29 2026 at 16:46):

It's 227 lines of code, mostly tests. The tests are completely exhaustive. The APIs were all cross-checked against Zig, Rust, C, and Go to try to conform to de facto standards. Every single function is implemented with a one-liner.

I had Claude look into calling directly into zig, but the Roc versions pretty much produce the same code as zig. The zig standard library doesn't do anything exotic like lookup tables that we would want to investigate.

    ## `a`-`z` to `A`-`Z`; every other byte, 128 to 255 included, unchanged.
    ## Zig `toUpper`, Rust `to_ascii_uppercase`, C `toupper`, and the per-byte
    ## rule of `Str.with_ascii_uppercased`.
    to_uppercase : U8 -> U8
    to_uppercase = |c| if c >= 'a' and c <= 'z' c.bitwise_xor(0x20) else c

Stream: show and tell

Topic: Roc ASCII

Hannes (May 03 2024 at 02:02):