This is a cool idea. There are other programming languages that have libraries that expose similar behavior. For instance, Rust has the uom crate, Haskell has the units package, and C++ has the header only library SI.
But there is something to be said about it being built in.
The web page says other libraries implement units whereas they implement dimensions. 1 cm and 1 inch has the same dimension, namely length, and you are able to add them together and get a correct result. seems nice. I don’t know if it’ll have any practical benefit but I like it.
For sure. It’d be nice to have the units in a separate namespace but at least Numbat won’t let you override identifiers already defined in the system of measure. I use Pint on Python - I usually keep the units in an identifier named u so they can’t get accidentally overridden. That means either using u.km for single units or u('g/cm^3') for composite units. It’d be great if the language could separate units e.g. as [km] or `` but getting a compact syntax to distinguish the units namespace without colliding with other language features would be tricky. I remember F# having a good syntax but didn’t dive that deep since it’s not used widely in my field.
