Dimensioned

A library for compile-time type checking of arbitrary unit systems.

This library currently comes with just SI units, but you can easily make your own by editing or importing unitsmaker.py. It has no tutorial yet, but it should be easy enough to emulate (just look at main()). Note: it does save a file to your computer and does zero sanity checking, so run it at your own risk.

To build,

cargo build

Here is an example of its use:

(excerpt of examples/vec.rs)

fn main() {
    let xhat: Dim<Unitless, Vector2d> = Dim(Vector2d{x: 1.0, y: 0.0});
    let yhat: Dim<Unitless, Vector2d> = Dim(Vector2d{x: 0.0, y: 1.0});

    let start = -xhat*m*13.0 + yhat*m*33.0;
    let end = xhat*m*26.0 - yhat*m*19.0;

    let displace = end - start;
    let time = s*26.0;
    let vel = displace/time;
    // Because we put norm() in a trait and implemented it for both Vector2d and Dim,
    // calling vel.norm() works as we want it to (returning Dim<Meter, ff64>). This is
    // the recommended way of accessing values inside a Dim.
    let speed = vel.norm();
    // Had we been unable or unwilling to implement norm() inside a trait, we could have
    // achieved the same behavior using the wrap() function, as follows:
    let speed2 = vel.wrap((vel.0).norm());
    println!("
A physicist was standing at {}.
Then she walked to {}, for a displacement of {}.
The walk took her {}, so she must have had a velocity of {}.
That's a speed of {}! Again, that's {}!", start, end, displace, time, vel, speed, speed2);

    let center = xhat*m*24.0 - yhat*m*17.0;
    let force = xhat*500.0*kg*m/s/s;
    let r = end-center;
    println!("
Now, she's standing next to a merry-go-round, centered at {}.
That is {} away from her. She decides to spin it, pushing with a force of {}.
That's a torque of {}!", center, r.norm(), force, r.cross(force));
}

with output:

A physicist was standing at (-13, 33) m.
Then she walked to (26, -19) m, for a displacement of (39, -52) m.
The walk took her 26 s, so she must have had a velocity of (1.5, -2) ms^-1.
That's a speed of 2.5 ms^-1! Again, that's 2.5 ms^-1!

Now, she's standing next to a merry-go-round, centered at (24, -17) m.
That is 2.828427 m away from her. She decides to spin it, pushing with a force of (500, 0) mkgs^-2.
That's a torque of 1000 m^2kgs^-2.

Run the example with

cargo run --example vec