Unchained VS libqalculate

Anything with a finite (200 is small even) number of units misses the algebraic structure of the problem mentioned in https://news.ycombinator.com/item?id=36988497 wherein multiplying|dividing two things gives you a (potentially) new unit which implies an open ended "space" of units.

To be concrete (hah!), in C++ a template meta-type with 12 signed integer parameters (6 numerators & 6 denominators for rational exponents of SI base units) might be one way to model it.

Unlike C++ template stuff, Nim macros (like Lisp macros) makes metaprogramming more like procedural programming - just against abstract syntax trees. I think that helps to shield some of this type complexity from users, but the documentation README https://github.com/SciNim/Unchained does better job than I can in an HN comment.

Of course, for unit system conversion, the number of dimensions (6 in SI, 3 in CGS/Gaussian) changes. So, for full generality you need compile-time (if you want static type integration/CT errors) linear algebra over a rational field (at least & conventionally) to project|inverse project. That might be theoretically possible in C++. I would think it very un-fun and unlikely to ever have been done. There's probably a Mathematica package, though.

I've recently written a units library for Nim [0]. It's still WIP, but it's already proven extremely useful for me as a physicist.

Thanks to Nim's strong type system and metaprogramming features, it allows for a fully compile time design, without any runtime overhead (in form of special unit objects or such things; everything is a `distinct float`).

In addition Nim's unicode support, the code even looks nice!

A more complex use case (I can link more if desired): [1]

[0]: https://github.com/SciNim/Unchained/

[1]: https://github.com/SciNim/Unchained/tree/master/examples

1) a scientific calculator with history and variables with a UI similar to https://sourceforge.net/projects/alt1-calculator/ that also can do units like https://qalculate.github.io/ 2) a tiny text chat direct message program that is similarly as easily accessible at Atl1 3) a minimalist dock of as many instances you would like similar to https://punklabs.com/rocketdock, and like where WIN opens the start menu, WIN + # should pop the dock

But unfortunately gravity is the first unit that I find is not supported :(

There's some talk about using g0 here https://github.com/Qalculate/libqalculate/issues/498 but that doesn't work in my version (I'm using an old version, hoping to update my OS this week). You can divide it by earth gravity if you know it by heart, though

    > 100 km/h / 0.956 s / 9.8 m/s^2

I personally use Qalculate (https://qalculate.github.io/), specifically their CLI version for this purpose. I'm not sure how well it compares to GNU Units, but it works well enough for my needs; and it's fairly simple using English-like syntax.

On the terminal, I use `qalc`[1]. It's a nice natural language calculator that does arithmetic, solves quadratic equations/linear systems, does unit conversions and even a bit of calculus. Combine it with a cli graphing tool and you can do pretty cool things.

Anything more complicated I'm probably ok with latency, so I open up wolframalpha and enter it there, again, in natural language.

[1] https://qalculate.github.io/

Btw, download qalculate.github.io and play around with it a bit. I use it for basically all the physics I do. Complete lifesaver.

Personally I use http://qalculate.github.io/ since I end up having to do unit conversions often, it's pretty handy for that

Btw: http://qalculate.github.io/ is nice. I use CLI version to fix my general math incompetence. Even does units nicely, for example, "how long it would take to download 82GB game on 50Mbit connection":

Mate Calculator: Seems a bit basic, when you can do so much more with Qalculate! https://qalculate.github.io/