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Karl Seguin

@karlseguin.com
379 followers 69 following 211 posts

coding www.openmymind.net

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Reposted by Karl Seguin
Daniel Hooper @danielchooper.bsky.social · 05/08/2026
@karlseguin.com I enjoyed your recent post. I use a segment array to avoid that ArrayList+Arena resize awkwardness. One other nice property: it doesn't move existing items when it grows. I wrote about it here: danielchasehooper.com/posts/segmen...
danielchasehooper.com
A Fast, Growable Array With Stable Pointers in C
My last article about generic data structures in C was written to set the stage for today’s topic: A data structure with constant time indexing, stable pointers, and works well with arena allocators. ...
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Karl Seguin @karlseguin.com · 05/08/2026
There's exactly 1 situation where humans are less slop than AI: documentation. AI generated documentation (comments, readme, commit messages, ...) is universally _awful_.
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Karl Seguin @karlseguin.com · 15/07/2026
😍😍😍😍
"By KOHCTAHT First-time GitHub contributor"
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Karl Seguin @karlseguin.com · 29/06/2026
This change that v8 made (a while ago)...hurt my head a little: github.com/v8/v8/commit...
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Karl Seguin @karlseguin.com · 23/06/2026
I wish #ziglang had a -DOOM=panic build flag. When set, any error.OutOfMemory is translated into a panic AND any function that only returns error.OutOfMemory becomes infallible.
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Reposted by Karl Seguin
SillyDevs Studio @sillydevs.bsky.social · 08/06/2026
LOL, it might not look like much, but to me, this is incredible. 9 people have already taken the time to download and play OVERCHARGE. That honestly means the world to me! Thank you to everyone checking it out. 💜📈 #gamedev #indiedev #solodev #pixelart
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Karl Seguin @karlseguin.com · 04/06/2026
du -sh .zig-cache/ 226G .zig-cache/ (╯°□°)╯︵ ┻━┻ #Ziglang
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Karl Seguin @karlseguin.com · 03/06/2026
I'm developing a hate for non garbage-collected runtimes. #Ziglang
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Karl Seguin @karlseguin.com · 31/05/2026
I updated Learning Zig to work with 0.16 www.openmymind.net/learning_zig/ #Ziglang
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Karl Seguin @karlseguin.com · 28/05/2026
I rather not know a metric than only knowing an average value.
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Karl Seguin @karlseguin.com · 27/05/2026
Where are all these companies / developers writing well thought-out, clean, secure and maintainable code that I keep hearing AI is threatening?
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Karl Seguin @karlseguin.com · 27/05/2026
For any hosted (i.e. not deployed on a desktop/mobile), #elixir is objectively better for anything you'd use ruby / node for. But Phoenix is so...ugh.
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Karl Seguin @karlseguin.com · 23/05/2026
I dearly miss Elixir.
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Karl Seguin @karlseguin.com · 22/05/2026
Blogged: On AI www.openmymind.net/On-AI/
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Karl Seguin @karlseguin.com · 20/05/2026
About 3x a week now. Claude says I'm violating its AUP for benign things. Today I asked Claude what was up with the error and it said "false positive", probably because we use words like "bug", "corrupt" etc. So I asked Claude to phone home again, but avoid those words...and it worked.
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Karl Seguin @karlseguin.com · 19/05/2026
A thread-safe pool of arena allocators, with different sized buckets (1K, 4K, 16K, 128K, 512K) is a good solution to many allocation problems.
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Karl Seguin @karlseguin.com · 19/05/2026
For a large agent-driven refactor, I benefit a lot from two things: 1 - Co-driving the first ~25% of the work. Helping nail a scope and shape and catching any assumptions / miscommunications. 2 - Spinning off a separate session (or taking over directly) early on stuck build / test failing.
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Karl Seguin @karlseguin.com · 17/05/2026
Coding agents are a tool, and, assuming they survive the bubble implosion, we're going to see (and already are seeing) effective individual / companies benefit from it, and incompetent individuals / companies suffer from it. 1/2
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Karl Seguin @karlseguin.com · 16/05/2026
Modern stdlib's should have a parser combinator.
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Karl Seguin @karlseguin.com · 16/05/2026
Let me enjoy this weekend by.... trying to get my networking heavy libraries to work with zig 0.16 half-baked networking i/o . . . on windows.
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Karl Seguin @karlseguin.com · 12/05/2026
I'm willing to grant that maybe Claude is effective for me because I code in a well documented/spec'd/ domain. But, at 800K context, slugging through a complex but well scoped piece of code, which is specific to the implementation, it can do anything in there ~100x faster and at least 5x better.
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Karl Seguin @karlseguin.com · 10/05/2026
if a $200/month tool is a significant productivity boost, that's going to be an issue for people living where $200 (USD) / month is a significant expense and, I would think, an issue for those countries as a whole.
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Karl Seguin @karlseguin.com · 06/05/2026
I've always been too dumb to learn Rust (I've tried!). I'm 100% sure I could pick it up with an AI-sidekick.
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Karl Seguin @karlseguin.com · 06/05/2026
There's 1 [software] management activity that trumps all others, and it isn't even close: reviewing pull requests.
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Karl Seguin @karlseguin.com · 29/04/2026
At least 1/2 of my Zig projects end up with a discriminatory type like `Binary{value: []const u8}` to be able to map byte vs string data. I just added one to lightpanda.
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Karl Seguin @karlseguin.com · 28/04/2026
Every C library should have 1 version that takes a null terminated string, and 1 that takes a ptr+len. It should be a law.
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Karl Seguin @karlseguin.com · 22/04/2026
It's a bit concerning that Claude Code is asking me to enter something like "I confirm that this is a legitimate part of the project and not part of some malware program".
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Karl Seguin @karlseguin.com · 20/04/2026
Zig 0.16's current state forced me to minimize the internal-use of std.Io that I added for 0.15. httpz is a bit of a mess now, but the 3/4 that reverted to the 0.14 way of doing things is _a lot_ neater and simpler.
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Karl Seguin @karlseguin.com · 23/02/2026
Enough tests tests that I feel confident pushing to main. But also not enough tests that I'm not surprised when something fails.
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Karl Seguin @karlseguin.com · 04/02/2026
In my old age, I prefer: (hasPending() == false) over: (!hasPending()). Fuck it, I said it.
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Karl Seguin @karlseguin.com · 04/02/2026
It's so easy to inject code into, what seems like, a [large] rebase.
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Karl Seguin @karlseguin.com · 01/02/2026
Said it before, I'll say it again. The reason #Ziglang should have a string type is purely so that code can discriminate between a string a binary data, which can be important in all types of cases usually involving things like interacting with other libraries or systems.
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Karl Seguin @karlseguin.com · 24/01/2026
It's simple: posix is better to program with than std.Io #Ziglang
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Karl Seguin @karlseguin.com · 22/01/2026
I'm starting to think unconditional WFH might not be right for most companies. For a well-managed company, it should probably be a per-employee policy. But for companies that can't deal with the drama that will cause, it should just default to hybrid.
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Karl Seguin @karlseguin.com · 16/01/2026
The Zig compiler (0.15.2) has been SIGABRT'ing on me daily for trivial errors. It can hard to review the current changes & figure out the error. Thankfully, this almost always finds the issue and turns a near-dealbreaker into a chuckle: find . -name "*.zig" -exec zig ast-check {} \;
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Karl Seguin @karlseguin.com · 15/01/2026
Engineering managers have 1 job right now: Find out which employees don't feel like coding agents are significantly increasing their productivity and figure out why.
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Karl Seguin @karlseguin.com · 13/01/2026
A commit message should explain why, not what. The diff already has what. Don't say "moved this to an ordered map"...that's redundant. Say _why_: "We need to execute these in insertion order as per the spec (ideally: link to spec)"
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Karl Seguin @karlseguin.com · 09/01/2026
That old joke, applied to tmux... How do you know if someone uses tmux? Don't worry...they'll tell you.
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Karl Seguin @karlseguin.com · 08/01/2026
Container tabs is the only reason I stick with Firefox. Can't believe it still isn't available in Chromium.
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Karl Seguin @karlseguin.com · 29/12/2025
I'm too dumb to know if the compiler will optimize my code, and too smart not to worry about it.
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Karl Seguin @karlseguin.com · 22/12/2025
Sometimes the #ziglang compiler just fails with no meaningful error. Just this: test └─ run test └─ compile test Debug native failure error: the following command terminated unexpectedly:
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Karl Seguin @karlseguin.com · 21/12/2025
There's virtually no code that I write now without an accompanying claude session. The $20/m plan suits my needs, but I could see myself doubling my usage (but not much more). I think comfort and success with it directly relates to your comfort and success with collaborative coding in general.
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Karl Seguin @karlseguin.com · 16/12/2025
WIP PR is at +62,029 −31,380 (and it isn't some linter / formatting).
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Karl Seguin @karlseguin.com · 26/11/2025
If I was building a web site/service today, I'd, if nothing else, at least consider Gleam.
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Karl Seguin @karlseguin.com · 17/11/2025
TIL: // zig fmt: off
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Karl Seguin @karlseguin.com · 29/10/2025
I find it fun. And there's probably a blog post or two in there. But the TL;DR would be - I've always found reading / reviewing code fun. It's the same, but a bit different.
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Karl Seguin @karlseguin.com · 29/10/2025
Claude also didn't like the way pg.zig's pool handled connections in a fail-state, so it wrote this: github.com/karlseguin/p...
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Karl Seguin @karlseguin.com · 28/10/2025
Claude didn't like my lame hash function. github.com/karlseguin/h...
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Karl Seguin @karlseguin.com · 09/10/2025
Everyone should try and use Google Jules just to see that there's clearly something wrong at Google.
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Karl Seguin @karlseguin.com · 08/10/2025
Spam on Fastmail is getting a bit bad.
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