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Introducing Numbat: A programming language with physical units as types (numbat.dev)
submitted 2 years ago by [M] to c/programming@programming.dev
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[–] 13 points 2 years ago (2 children)

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.

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  • [–] 5 points 2 years ago (1 child)

    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.

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  • [–] 3 points 2 years ago* (last edited 2 years ago)

    I can't talk about the other libraries but the uom crate does the same thing.

    The dimensions are encoded as a vector of generics, allowing you to get the correct unit even when dividing a distance by time for example.

    It's quite the clever use of Rusts type system.

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  • [–] 1 point 2 years ago

    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.

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