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- Hacker News
- Edit: Whoops. My bad. This must have been a HN "second chance" winner.by Jblx2
- Er, that's this submission.by ColinWright
- That looks like a link right back to this thread?by badc0ffee
- btw if you turn the iphone calc into landscape mode and switch you scientific calc it does Ramanujan's constant without rounding, but stops after the twelve 9s.by htx80nerd
- Correct, but if you don't know the next digit is 2, you can think it's all 9s, another representation of an integer number.by dimview
- It would also be fun to have a full computer algebra system (like maxima) on a phoneby piinbinary
- That should be doable, too. Maybe as a next project.by dimview
- by xigoi
- Very interesting, thank you for posting! I'm curious - roughly how many tokens do you think you used during the initial port and subsequent bug hunting and fixes?by jagraff
- For Opus 4.8, 142.3k input, 2.0m output for the entire project. No longer have access to Fable 5 to check.by dimview
- I don't get why this is a big deal. All the calculators I've used have been rectangle.
- Author here. I could not find a constructive‑reals calculator on iPhone, so I ported the engine Android uses: Hans Boehm's com.hp.creals plus AOSP's UnifiedReal/BoundedRational. Used Opus 4.8 to do the port and Fable 5 for the review.
Fable 5 caught a couple of real concurrency bugs the port introduced while adapting Java's synchronized/AsyncTask to Swift concurrency, including one that was a memory‑safety bug on shared singletons like π, not just a wrong digit. None would have shown up in the unit tests. Writeup has the details.
It's an early iPhone TestFlight beta (link in the post); happy to go deep on either the constructive‑reals side or the AI‑assisted‑dev side.
by dimview - The old HP calculators, and their emulators, have a computer algebra system, for symbolic maths, that supported this. The user interfaces leave much to be desired, but some also have reverse Polish notation!by nomel
- Maybe you should correct the errors in your post before worrying about the code.by NetMageSCW
- > I built one, by porting Boehm’s engine. > It’s 2026, so I didn’t hand-write the port. I directed Opus 4.8 to translate the source line by line into Swift
I wish I could filter out stuff like this. Cool work by Hans Boehm, but what's the value add in this blog post.
by bla3 - Read. Guy knows what he's doing.by B1FF_PSUVM
- > Hans Boehm built a Java library for this in the 1980s and 90s
Hans is such a prolific programmer that he wrote a Java library before Java was even invented?
by __alexs - Well, you know, you go into your Smalltalk-80 workstation for a hack sesh, and an all-nighter later you end up with an implementatkon of Swing...by nxobject
- The article has so many of the hallmarks of LLM writing, naturally it will have some hallucinated factoids too. "What that gives you: [bullet list]", "What got ported: [bullet list]", "foo: x, y, just z"
Boehm's Java library has copyright dates of 1999 and 2001-2004. https://www.hboehm.info/new_crcalc/CR.java
The whitepaper was only published in 2005: https://www.sciencedirect.com/science/article/pii/S156783260...
I have a dimview now of the blog, and of this Swift port of the library, indeed.