Macro vector 

macro_rules! vector {
    ($x:tt = $xx:expr, $y:tt = $yy:expr, $z:tt = $zz:expr $(,)?) => { ... };
    (n = $n:expr, e = $e:expr, d = $d:expr; in $in:ty) => { ... };
    (e = $e:expr, n = $n:expr, u = $u:expr; in $in:ty) => { ... };
    (f = $f:expr, r = $r:expr, d = $d:expr; in $in:ty) => { ... };
    (x = $x:expr, y = $y:expr, z = $z:expr; in $in:ty) => { ... };
}

Quickly construct a Vector using named components.

This macro allows constructing Vectors for a coordinate system by naming the arguments according to its CoordinateSystem::Convention. Using the wrong named arguments (eg, trying to make a NedLike Vector using f = ) will produce an error at compile-time.

For NedLike, use:

vector! {
    n = Length::new::<meter>(1.),
    e = Length::new::<meter>(2.),
    d = Length::new::<meter>(3.),
}

For FrdLike, use:

vector! {
    f = Length::new::<meter>(1.),
    r = Length::new::<meter>(2.),
    d = Length::new::<meter>(3.),
}

For RightHandedXyzLike, use:

vector! {
    x = Length::new::<meter>(1.),
    y = Length::new::<meter>(2.),
    z = Length::new::<meter>(3.),
}

The macro also allows explicitly specifying the coordinate system In for the returned Vector (which is otherwise inferred) by suffixing the component list with ; in System, like so:

system!(struct Frd using FRD);
vector! {
    f = Length::new::<meter>(1.),
    r = Length::new::<meter>(2.),
    d = Length::new::<meter>(3.);
    in Frd
}

The macro automatically determines the vector unit type based on the units provided:

// Creates Vector<PlaneFrd, Z0> / LengthVector (length vector)
let position = vector!(
    f = Length::new::<meter>(1.0),
    r = Length::new::<meter>(0.0),
    d = Length::new::<meter>(0.0);
    in PlaneFrd
);

// Creates Vector<PlaneFrd, N1> / VelocityVector (velocity vector)
let velocity = vector!(
    f = Velocity::new::<meter_per_second>(5.0),
    r = Velocity::new::<meter_per_second>(0.0),
    d = Velocity::new::<meter_per_second>(0.0);
    in PlaneFrd
);

// Creates Vector<PlaneFrd, N2> / AccelerationVector (acceleration vector)
let acceleration = vector!(
    f = Acceleration::new::<meter_per_second_squared>(2.0),
    r = Acceleration::new::<meter_per_second_squared>(0.0),
    d = Acceleration::new::<meter_per_second_squared>(0.0);
    in PlaneFrd
);