Jan Stehlík
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jstehlik.cz
Jan Stehlík
@jstehlik.cz
240 followers 370 following 190 posts
I make apps https://jstehlik.cz
jstehlik.cz
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jstehlik.cz
Jan Stehlík @jstehlik.cz · 4h
Liquid Glass is expensive. Battery lasts one hour less.
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jstehlik.cz
Jan Stehlík @jstehlik.cz · 6h
That makes sense. Though I’m not sure why they went with this tiny performance gain only to turn iOS26 into a power hog 😆
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jstehlik.cz
Jan Stehlík @jstehlik.cz · 13h
wait what? Why would it not trigger updates for equatable properties? Is that to say that the update will not trigger if an equatable property *is not* changed, i.e. newValue == oldValue?
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jstehlik.cz
Jan Stehlík @jstehlik.cz · 1d
2025 - the year when all developers the world over, all of them at once, were absolutely right.
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Jan Stehlík @jstehlik.cz · 3d
linking to X from Bluesky?
a man in a military uniform is standing in front of a room with people sitting at tables .
ALT: a man in a military uniform is standing in front of a room with people sitting at tables .
media.tenor.com
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jstehlik.cz
Jan Stehlík @jstehlik.cz · 13d
please please please make an iPad port, this would work really well on that platform (as do Crying Suns)
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jstehlik.cz
Jan Stehlík @jstehlik.cz · Oct 1
I still don't get how y'all get LLMs to output useful code.

I find them useful for isolated snippets and documentation, but they completely break down on anything more complex.

There is a threshold at which the output stops being useful and instead becomes a burden.
a dog wearing glasses sits at a computer keyboard
ALT: a dog wearing glasses sits at a computer keyboard
media.tenor.com
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jstehlik.cz
Jan Stehlík @jstehlik.cz · Sep 25
Reason #379430 to not use Siri
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jstehlik.cz
Jan Stehlík @jstehlik.cz · Sep 21
maybe something for @massicotte.org (or anyone else) to turn into a blog post. I just feel like this is not addressed as much as it should be, given how important it is. It's easy to think that "await" tells the actor to sit and twiddle its thumbs. Which is inaccurate.
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jstehlik.cz
Jan Stehlík @jstehlik.cz · Sep 21
One under-reported and easily misunderstood concept of @swift.org concurrency is blocking vs suspension. I created a simple gist for experimentation, which helped me solidify these foundational concepts. gist.github.com/blu-Fox/c184...
A simple view to test 3 async-related concepts: 1. blocking a thread 2: suspending a task 3: overwhelming a thread
A simple view to test 3 async-related concepts: 1. blocking a thread 2: suspending a task 3: overwhelming a thread - TaskSuspensionView.swift
gist.github.com
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jstehlik.cz
Jan Stehlík @jstehlik.cz · Sep 20
I'm sorry you're having this trouble. I would start by checking the CloudKit dashboard, and verifying where the data actually gets stored (development or production). That will tell you a lot. Also, double-check that your Xcode is not inadvertently accessing the production version of CloudKit.
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jstehlik.cz
Jan Stehlík @jstehlik.cz · Sep 20
Before you do this, you should investigate the other part, which is that preview (in-memory) data should not be persisted, and therefore should not be backed up, and therefore should not be mixed in with your personal data in the development schema.
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jstehlik.cz
Jan Stehlík @jstehlik.cz · Sep 20
Not at all. But I see you have no interest in a meaningful conversation. So we can leave it at that.
jstehlik.cz
Jan Stehlík @jstehlik.cz · Sep 20
Yes, exactly! A version from Xcode and a version from App Store will sync from separate containers.
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jstehlik.cz
Jan Stehlík @jstehlik.cz · Sep 19
By the way this is designed so you can tweak your model during development, before pushing it to users. After you push it, the model cannot be erased (though it can be expanded); this is to protect the integrity of your users' data :-)
jstehlik.cz
Jan Stehlík @jstehlik.cz · Sep 19
If you're using your own app, you should do it from TestFlight or App Store. That way, your personal data (as a user) and your debug data (as a developer) will never get mixed up, even if preview uses persistence by mistake or bug.
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jstehlik.cz
Jan Stehlík @jstehlik.cz · Sep 19
Ah, that's your problem. Yes, there is a difference. When you develop your app and test CloudKit, everything sits in a separate (development) schema. When you are ready, you *manually* push your model to the actual (production) schema. Then, it can be used from TestFlight/AppStore.
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jstehlik.cz
Jan Stehlík @jstehlik.cz · Sep 19
Mopping is actually disappearing pretty fast, what with half-empty office places and big robots in malls. Plumbing is where it's at.
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jstehlik.cz
Jan Stehlík @jstehlik.cz · Sep 19
I suppose that could happen with development version data if you're not using the in-memory store option. But your actual data (which should sit isolated in the production version of iCloud) should remain unaffected.
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jstehlik.cz
Jan Stehlík @jstehlik.cz · Sep 19
If you follow this default setup, it cannot happen that preview data populates your production data. It also cannot happen that simulator data populates your production data.
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Jan Stehlík @jstehlik.cz · Sep 19
When you or other people use your app, the data should be persisted in iCloud’s production version. When you use simulator or test device, data should be in iCloud’s development version. When you use previews, data should not be persisted at all.
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jstehlik.cz
Jan Stehlík @jstehlik.cz · Sep 19
I feel like you’re mixing up 2 things. 1) In-memory data (for previews) vs persisted data (for simulator and test devices, using debug iCloud). And 2) debug iCloud vs production iCloud (on TestFlight and App Store).
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jstehlik.cz
Jan Stehlík @jstehlik.cz · Sep 19
That’s how it always worked. The papyrus industry was wiped out by paper. Monks writing manuscripts lost their jobs to the printing press. Factories replaced millions of craftsmen. Postmen lost their jobs to e-mail. Yet here we are, building new jobs and opportunities on all that job destruction.
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jstehlik.cz
Jan Stehlík @jstehlik.cz · Sep 19
I disagree. It's great to love one's profession, but you shouldn't anchor your entire existence around it. If times change, change with them. Some doors may close, and others will open. AI is here to stay, and despite its many flaws, it also creates many opportunities.
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jstehlik.cz
Jan Stehlík @jstehlik.cz · Sep 19
Wait what? How is that even possible? Xcode should be running in debug environment. Only builds in TestFlight and App Store access the production environment.
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