At the risk of coming across as being a spoilsport, I think when someone says "anyone can write a calculator app", they just mean an app that simulates a pocket calculator (which is indeed pretty easy) as opposed to one which always gives precisely the right answer (which is indeed impossible). Also, you can avoid the most embarrassing errors just by rearranging the terms to do cancellation where possible, e.g. sqrt(2) * 3 * sqrt(2) is absolutely precisely 6, not 6 within some degree of approximation.
> as opposed to one which always gives precisely the right answer (which is indeed impossible)
Per the article, it's completely possible. Frankly I'd say they found the obvious solution, the one that any decent programmer would find for that problem.
It... really doesn't seem like a lot of effort and thought. I feel like anyone who's implemented a command algebra for anything is already halfway there.
