Simple RPN Calculator

Posted: August 7, 2023 | Categories: Mobile Development, Miscellaneous, Flutter

On my 18th birthday, my high school girlfriend gave me an Hewlett Packard 41CV calculator; I loved that thing. Owning it introduced me to Reverse Polish Notation (RPN) as well as extensible computers. It wasn't a calculator, it was a programmable computer you could hold in your hand and I programmed the hell out of that thing. It allowed you to plugin modules, I think it had 4 slots and I had a whole bunch of modules. This thing was even something they used to calculation on the space shuttle: Calculator, Hand-held, HP41.

That particular device is long gone and I've burned through a couple of replacement devices over the years. I can use a traditional calculator, but I do much better with RPN-based ones. I've played around with the different RPN calculators on Android and iOS, but none of them meet my needs. I have one on Android that's excellent, but so many of these app developers try too hard to mimic the layout and look of HP Calculators, so for this particular one, I can never seem to find the X<>Y button when I need it.

Anyway, I drew out a wireframe diagram of the app's UI (see below) and I've open sourced the code so you can follow along as I build this thing. No guarantees for when I'll finish this thing, but I have some time over the next few weeks to dedicate to this, so it may not be too long. You can find the code in Simple RPN Calculator.

I'm writing the app using Flutter for a variety of reasons:

1. I LOVE writing Flutter apps
2. Using Flutter allows me to deliver mobile apps as well as a web application. I can even build this thing for Windows and macOS so I can run the app anywhere.
3. Did I mention that I LOVE writing Flutter apps?

Stay tuned on this one, I'l share real app screen shots when I make real profgress.

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Header image: Photo by ilgmyzin on Unsplash.