Checking out kalc, a scientific/graphing calculator written in Rust. I've been looking for a good calculator, and I don't need all the features in it, although sometimes I do find myself wishing I could just graph something real quick.
So far it is fantastic! It's basically a shell in a terminal that accepts all sorts of notation, sqrt(x), x//2, x(1/2) and x**(1/2) for example all give you the square root of x. So no matter what sort of notation you're used to for doing math, whether it's from some programming language you use a lot, or regular algebraic notation, it has you covered. It also has all the built in functions you would ever need, all trigonometric functions and everything else you could ask for, logic operators, bitwise operators, everything. It let's you change notation. It allows you to use Greek characters, has all the constants you'd use in day to day life like e, π and i, and you can define functions and constants yourself in the configuration. Additionally, it loads files. The only things I haven't figured out yet is how to do binary and hex conversions, I wonder if those are built in or not.
I've tried numerous different calculators, GUI calculators, TUI calculators, programmers calculators, scientific calculators, numerous different graphing calculator emulators, and this is so far the one that does everything in a sane way. Usually I'll just load a REPL or the python interpreter to do math real quick because it works better than every calculator I've tried. If you use a calculator regularly on your machine this one will probably do everything you need and stay out of your way.
It depends on gnuplot for graphing.