We Made Our Own Calculator

05/26/2022

Before I start: to those who wrote to me on J-Card Template, I hear you. There have been requests to fit more cards into a page, implement fold-out cards, and even templates for MiniDisc. The template was forked from Blaine Murphy's, and all I did is to add convenience features on top of it. So I will need to study how he lays down the card. Don't worry: they will come, one at a time, but I can't tell exactly when. And yes, the LICENSE file needs to be updated.

Calc is currently our oldest active project spanning over eight years of development. It provides an interface to the host's shell arithmetic features as a calculator. It has been very obvious to us that said features are not designed to be calculators, especially with no floating-point arithmetic.

After dropping Windows in late 2019, we attempted to bring fractional precision to elementary divisions like 1 / 9. Normally, Calc returns a 0 for that, while our workaround produces exactly 0.111111111111111111 instead. As you might have guessed, this approach is elementary, and extrapolating such to other limitations can get extremely difficult.

Overcoming limitations has been a fun(?) part in our projects. In EDENrm: our Rainmeter skin suite, we made a rudimentary audio player that detects the end of an audio file with silence. We made similar audio players for PowerPoint too--without the silence detection. It has indeed been a long time since we pulled off tricks of those kinds. So, as a successor to Calc, we completed a math library for Bash (a shell commonly found in Unix-based operating systems).

Pnic is independent of Bash's arithmetic features; it does math with string manipulations and lookup tables, like those hand methods taught in early and middle schools. While its runtime performance is not very hot, it aims to be able to work on any real number imaginable--correctly of course. So--in theory--Pnic can multiply ten-million-digit numbers just fine. And yes, Pnic does floating-point arithmetic.

Division however, still relies on Bash's arithmetic features, so you will have to excuse us while we figure out ways to divide like the rest. For now, we injected our workaround from Calc, which not only overcame the limits of the dividend, but also worsens rounding errors.

But wait, there's more!

Introducing KESIMATE, a pocket calculator simulator that uses Pnic for its calculations. In addition to what's already in boring calculator programs, it simulates power, fraction, and percentage. It also has sign change and square root features. Only KESIMATE matches the behavior of real, physical pocket calculators--as far as my collection goes.

You can find the links to the project pages in the home page under the Projects section.

Integrating Pnic into Calc could take a lifetime because we will need to implement an expression parser. So, that is definitely off the table, but we will still maintain Calc as we see fit.