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Programming in System RPL

hpcalc.org

23 pointsbrudgers17 comments

I'm still looking for an ideal calculator, a fully programmable ruggedized device with a small form factor, a powerful CAS, an outstanding keyboard, clock and alarm, a sun-readable display (e-ink), and, most importantly, weeks of battery life.

But I have to second cjsuk, User RPL and System RPL are not programming languages you'd want to use nowadays for larger projects. Personally, I'd like to see Lisp on such a device, but any kind of Basic, Pascal or Lua like language with built-in hashtables and structures should be fine.

Anyway, as it looks now, the HP50g will be the last calculator I own. The companies apparently think that the market isn't big enough. I believe there is a demand for a machine like the above one, especially if it's also water proof, but maybe I'm wrong.

I get the feeling it will never happen. The nearest thing to this was the TI Voyage 200. Everything went downhill after that.

With enough dedication you can program an arm chip or an ESP32 (dual core 32bits 100MHz) < 10$ a piece.

eInk displays are also below 10$ but except for very recent and/or expensive models the refresh rate is not appropriate (unbearable IMO)

It's always the software that is the problem however.

Not sure I like eInk displays at all.

I like minimalism, a few shades of gray and one color (maybe two) could be enough for calcing. And the consumption too.. but the delay is too much.

> The companies apparently think that the market isn't big enough. I believe there is a demand for a machine like the above one

At what price point and volume? I feel like there would be ton of development work (custom sw stack, and just the mechanical aspects), and the manufacturing probably won't be cheap either (especially if you can't utilize the economics of scale), which makes a problematic equation for what is ultimately a niche item.

Maybe the DM42?

programmable? kinda

rugged? a steel or titanium case, not sure, but yes

keyboard? should be good based on prior form

clock? yes

alarm? don't think so

e-ink? yes

weeks of battery? yes

This device may be hackable in the future, but it will be released based on free42 and Intel's quad-precision decimal library which I think will make it the most accurate handheld calculator.

Another option might be the numworks calculator[2] which runs python and is open source. But doesn't meet your other criteria.

A third option might be the Gemini - a folding clamshell that runs linux.[3] or even the pocket chip? [4]

[1] https://www.swissmicros.com/dm42.php

[2]https://www.numworks.com

[3]https://www.indiegogo.com/projects/gemini-pda-android-linux-...

[4]https://getchip.com/pages/pocketchip

PocketChip: only 5 h battery life, not durable, but otherwise would be ideal - but with 5h battery life it's nothing but a useless gimmick

DM42: no alarm, too limited programming (basically a HP42 clone), no CAS, otherwise it would be ideal

gemini pda: too short battery life, way too expensive

numworks: kind of cool, but doesn't meet the criteria either, and it currently still has math problems (accuracy changes with every firmware update, the least thing I want from a calculator is inconsistent floating point arithmetic)

If I knew more about electronics, I'd make my own device but my life is unfortunately too short and too busy for that. I guess you can't always get what you want. ;)

As a former RPL programmer out of self interest, I think I’d rather gouge my eyes out now. It’s one of those languages, like Perl, where you come back to a project later and can’t understand any of it or remember how to write it.

I respect people who managed to build a working CAS in it however!

I still own an HP50g for the sake of nostalgia but it has been replaced with python and a new Casio FX-991EX now.

Does the casio run python? I like the idea of having a portable machine I can write quick programs in, but some of these calculator languages are horrible. I'd rather write it in something a bit more mainstream like python or R.

The numworks calculator[1] has got a kinda beta implementation of python. The other device I was thinking of was the Gemini (modern day psion) or something similar.

[1]https://www.numworks.com

No it doesn't. It's really just a scientific calculator with a solver built in. It handles perhaps 95% of my requirements pretty well. Anything more complicated than that heads to a mac. I've been using scipy, matplotlib and sympy on that.

The basic graphing calculators from Casio, while not overly powerful have a programming language that you can effectively drive on the device very easily. I've seen people do some amazing stuff on them.

Although I agree with your general feeling (RPL is mostly a write-only language), RPL is still a quite valid language to add useful formulas in some menus.

For example, I still have many programs for electrical circuits, like adding resistances in parallel, and those ones are easy to understand. Full programs with many functions and branches? I had no idea what I was doing.

That's exactly what I was using mine for.

  << INV SWAP INV + INV >> 'RPAR' STO

Then I realised I don't bother with it. Can get close enough in my head. I only want to solve for one variable so the Casio gets full marks there.

LOL, i recall programming in RPL and considering doing SystemRPL but it looked as hard as programming the HP48 in assembly, without assembly's performance (which was way faster than "user" RPL, by the way.)

Oh, Carsten Dominik again.. I forgot he was a long time RPLer. And now an Emacs REPLer.

Funny how many HPcalc users naturally liked Emacs

Let me tell you about sysrpl. I'm well.

RPL is a fine language. System RPL gave me Tourette’s syndrome.

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