Lukas Atkinso: Net-Negative Cursor
(lukasatkinson.de)
from HaraldvonBlauzahn@feddit.org to programming@programming.dev on 01 Jun 04:07
https://feddit.org/post/13417271
from HaraldvonBlauzahn@feddit.org to programming@programming.dev on 01 Jun 04:07
https://feddit.org/post/13417271
What I think in addition to what Atkinso writes: If you just strip arbitrary bytes that happen to be equal in value to the numeric value of ASCII control characters or whitespace, how can you be sure that you don’t destroy valid non-whitespace unicode symbols?
You can’t! This will work only of you have actually ASCII input.
#programming
threaded - newest
let mut bytes = vec![0u8; len as usize]; buf.read_exact(&mut bytes)?; // Sanitize control characters let sanitized_bytes: Vec<u8> = bytes.into_iter() .filter(|&b| b >= 32 || b == 9 || b == 10 || b == 13) // Allow space, tab, newline, carriage return .collect();This implicitly, and wrongly, swaps the interpretation of the input from UTF8 text to pure ASCII.
In UTF8, all bytes that are not an ASCII character have the high bit set.
This person Unicodes
You are right with this. But still, in Rust, a vector of u8 is different from a sequence of unicode characters. This would not work in Python3 either, while it’d work in Python2.
yeah it’s incorrect bc it destroys multibyte characters, butno idea what you’re saying about u8 being a different type from unicode. the original code was reading bytes and converting them too? the typing isn’t the issue, you can still store utf8 as a series of bytesIt doesn’t. As the poster two levels up said, all bytes that don’t represent an ASCII character have the high bit set, even the follow-up bytes in multibyte sequences. So the condition
b >= 32will match and preserve them.yeah fair enough. that wasn’t really my point and I wasn’t paying attention
No, the filter is correct even for UTF-8. Any ASCII character is exactly unchanged in UTF-8 (part of the reason it is popular). Since this code only filters out ASCII characters it works fine with ASCII or UTF-8.
The link is broken. Looks like code was accidentally pasted there.
Cleaned up link: lukasatkinson.de/2025/net-negative-cursor/
Thanks, I fixed it!
Not a coder but I grasped enough.
Lastly, I’d like to know where the AI got the idea from. Sounds like pizza glue.
I don’t think this is a very interesting article. We already know AI suggests nonsense a lot of the time. That in no way demonstrates that it is net-negative. In my experience it’s a net positive even accounting for the times it gets things wrong.
Yes you do have to review its code closely. News at 10.
It is kind of funny that they picked an example where it made an obvious mistake for their hero image though.