Yes - you haven't seen the full scope until you confront unit system conversions as alluded to in my other comment (https://news.ycombinator.com/item?id=3698849

Yes - you haven't seen the full scope until you confront unit system conversions as alluded to in my other comment (https://news.ycombinator.com/item?id=36988497 https://news.ycombinator.com/item?id=36988497). There should also be conversions to/from SI|CGS and "natural units" (particle physics) and "gravitational units" (general relativity - G=c=1). The "input/output" can be a bit more subtle, too - since you may need to tell the converter the abstract physical kind/"meta type" of the thing like "energy" or "momentum" or "charge" to fully define what might happen (and in some ideal world get back an expression with powers of G's and c's in there symbolically rather than only numerically). Some of this shows up in an unresolved issue on that Nim library I mentioned[1]: https://github.com/SciNim/Unchained/issues/8 https://github.com/SciNim/Unchained/issues/8 EDIT: { One reason to preserve a symbolic capability is that some constants have resisted precise measurement for centuries - G is still only known to about 5 decimals [2] - and you don't want round-trip unit conversion to add such errors to the calculation. } [1] https://news.ycombinator.com/item?id=36988225 https://news.ycombinator.com/item?id=36988225 [2] https://en.wikipedia.org/wiki/Gravitational_constant#Modern_value https://en.wikipedia.org/wiki/Gravitational_constant#Modern_...