nalgebra/src/geometry/swizzle.rs

use crate::base::allocator::Allocator;
use crate::base::{DefaultAllocator, DimName, Scalar};
use crate::geometry::{Point, Point2, Point3};
use typenum::{self, Cmp, Greater};

macro_rules! impl_swizzle {
    ($( where $BaseDim: ident: $( $name: ident() -> $Result: ident[$($i: expr),+] ),+ ;)* ) => {
        $(
            impl<N: Scalar + Clone, D: DimName> Point<N, D>
            where
                DefaultAllocator: Allocator<N, D>,
                D::Value: Cmp<typenum::$BaseDim, Output=Greater>
            {
                $(
                    /// Builds a new point from components of `self`.
                    #[inline]
                    pub fn $name(&self) -> $Result<N> {
                        $Result::new($(self[$i].inlined_clone()),*)
                    }
                )*
            }
        )*
    }
}

impl_swizzle!(
    where U0: xx()  -> Point2[0, 0],
              xxx() -> Point3[0, 0, 0];

    where U1: xy()  -> Point2[0, 1],
              yx()  -> Point2[1, 0],
              yy()  -> Point2[1, 1],
              xxy() -> Point3[0, 0, 1],
              xyx() -> Point3[0, 1, 0],
              xyy() -> Point3[0, 1, 1],
              yxx() -> Point3[1, 0, 0],
              yxy() -> Point3[1, 0, 1],
              yyx() -> Point3[1, 1, 0],
              yyy() -> Point3[1, 1, 1];

    where U2: xz()  -> Point2[0, 2],
              yz()  -> Point2[1, 2],
              zx()  -> Point2[2, 0],
              zy()  -> Point2[2, 1],
              zz()  -> Point2[2, 2],
              xxz() -> Point3[0, 0, 2],
              xyz() -> Point3[0, 1, 2],
              xzx() -> Point3[0, 2, 0],
              xzy() -> Point3[0, 2, 1],
              xzz() -> Point3[0, 2, 2],
              yxz() -> Point3[1, 0, 2],
              yyz() -> Point3[1, 1, 2],
              yzx() -> Point3[1, 2, 0],
              yzy() -> Point3[1, 2, 1],
              yzz() -> Point3[1, 2, 2],
              zxx() -> Point3[2, 0, 0],
              zxy() -> Point3[2, 0, 1],
              zxz() -> Point3[2, 0, 2],
              zyx() -> Point3[2, 1, 0],
              zyy() -> Point3[2, 1, 1],
              zyz() -> Point3[2, 1, 2],
              zzx() -> Point3[2, 2, 0],
              zzy() -> Point3[2, 2, 1],
              zzz() -> Point3[2, 2, 2];
);