This is great, I use `bc` a lot at work (particularly when away from desk and my actual calculator) but I'll probably bookmark this to use instead.
One bit of very minor feedback:
`x^y tonnes` errors 'exponent must be unitless'. The more expected (IMO) grouping `(x^y) tonnes` works, so why not have the non-error grouping be the implied one, when no parens given?
I hadn't thought about that before but I think you're right, I've added it to my roadmap.
Getting operator precedence right has been pretty fraught tbh. For example "1km / 3 hours" is evaluated as "(1km) / (3 hours)", but "1 / 3 hours" is evaluated as "(1 / 3) hours", which is odd from a PL perspective, but I think it's more intuitive from a user perspective for this sort of thing.
One bit of very minor feedback:
`x^y tonnes` errors 'exponent must be unitless'. The more expected (IMO) grouping `(x^y) tonnes` works, so why not have the non-error grouping be the implied one, when no parens given?