A calculator that doesn't round

__alexs•about 2 hours ago

> 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?

tomjakubowski•about 1 hour ago

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.

nxobject•about 1 hour ago

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...

bla3•about 1 hour ago

> 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.

dimview•3 days ago

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.

NetMageSCW•about 1 hour ago

Maybe you should correct the errors in your post before worrying about the code.

nomel•about 1 hour ago

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!

quixoticelixer-•about 1 hour ago

I don't get why this is a big deal. All the calculators I've used have been rectangle.

jagraff•about 2 hours ago

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?

piinbinary•about 2 hours ago

It would also be fun to have a full computer algebra system (like maxima) on a phone

Jblx2•about 2 hours ago

Edit: Whoops. My bad. This must have been a HN "second chance" winner.

badc0ffee•about 1 hour ago

That looks like a link right back to this thread?

ColinWright•about 1 hour ago

Er, that's this submission.

htx80nerd•about 2 hours ago

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.

A calculator that doesn't round

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