Merge pull request #899 from dimforge/point_macro

Add a point! macro for constructing points

Author: sebcrozet

nalgebra-macros/src/lib.rs

@@ -280,3 +280,34 @@ pub fn dvector(stream: TokenStream) -> TokenStream {
     };
     proc_macro::TokenStream::from(output)
 }
+
+/// Construct a fixed-size point directly from data.
+///
+/// **Note: Requires the `macro` feature to be enabled (enabled by default)**.
+///
+/// Similarly to [`vector!`], this macro facilitates easy construction of points.
+///
+/// `point!` is intended to be the most readable and performant way of constructing small,
+/// points, and it is usable in `const fn` contexts.
+///
+/// ## Examples
+///
+/// ```
+/// use nalgebra::point;
+///
+/// // Produces a Point3<_>
+/// let v = point![1, 2, 3];
+/// ```
+#[proc_macro]
+pub fn point(stream: TokenStream) -> TokenStream {
+    let vector = parse_macro_input!(stream as Vector);
+    let len = vector.len();
+    let array_tokens = vector.to_array_tokens();
+    let output = quote! {
+        nalgebra::Point::<_, #len> {
+            coords: nalgebra::SVector::<_, #len>
+                        ::from_array_storage(nalgebra::ArrayStorage([#array_tokens]))
+        }
+    };
+    proc_macro::TokenStream::from(output)
+}

nalgebra-macros/tests/tests.rs

@@ -1,9 +1,10 @@
 use nalgebra::{
     DMatrix, DVector, Matrix1x2, Matrix1x3, Matrix1x4, Matrix2, Matrix2x1, Matrix2x3, Matrix2x4,
-    Matrix3, Matrix3x1, Matrix3x2, Matrix3x4, Matrix4, Matrix4x1, Matrix4x2, Matrix4x3, SMatrix,
-    SVector, Vector1, Vector2, Vector3, Vector4, Vector5, Vector6,
+    Matrix3, Matrix3x1, Matrix3x2, Matrix3x4, Matrix4, Matrix4x1, Matrix4x2, Matrix4x3, Point,
+    Point1, Point2, Point3, Point4, Point5, Point6, SMatrix, SVector, Vector1, Vector2, Vector3,
+    Vector4, Vector5, Vector6,
 };
-use nalgebra_macros::{dmatrix, dvector, matrix, vector};
+use nalgebra_macros::{dmatrix, dvector, matrix, point, vector};
 
 fn check_statically_same_type<T>(_: &T, _: &T) {}
 
@@ -106,6 +107,19 @@ fn vector_small_dims_exhaustive() {
     assert_eq_and_type!(vector![1, 2, 3, 4, 5, 6], Vector6::new(1, 2, 3, 4, 5, 6));
 }
 
+// Skip rustfmt because it just makes the test bloated without making it more readable
+#[rustfmt::skip]
+#[test]
+fn point_small_dims_exhaustive() {
+    assert_eq_and_type!(point![], Point::<i32, 0>::origin());
+    assert_eq_and_type!(point![1], Point1::<i32>::new(1));
+    assert_eq_and_type!(point![1, 2], Point2::new(1, 2));
+    assert_eq_and_type!(point![1, 2, 3], Point3::new(1, 2, 3));
+    assert_eq_and_type!(point![1, 2, 3, 4], Point4::new(1, 2, 3, 4));
+    assert_eq_and_type!(point![1, 2, 3, 4, 5], Point5::new(1, 2, 3, 4, 5));
+    assert_eq_and_type!(point![1, 2, 3, 4, 5, 6], Point6::new(1, 2, 3, 4, 5, 6));
+}
+
 #[test]
 fn vector_const_fn() {
     // Ensure that vector! can be used in const contexts
@@ -115,6 +129,15 @@ fn vector_const_fn() {
     const _: Vector6<i32> = vector![1, 2, 3, 4, 5, 6];
 }
 
+#[test]
+fn point_const_fn() {
+    // Ensure that vector! can be used in const contexts
+    const _: Point<i32, 0> = point![];
+    const _: Point1<i32> = point![1];
+    const _: Point2<i32> = point![1, 2];
+    const _: Point6<i32> = point![1, 2, 3, 4, 5, 6];
+}
+
 // Skip rustfmt because it just makes the test bloated without making it more readable
 #[rustfmt::skip]
 #[test]
@@ -195,6 +218,23 @@ fn dmatrix_builtin_types() {
     let _: DMatrix<f64> = dmatrix![0.0, 1.0; 2.0, 3.0];
 }
 
+#[test]
+fn point_builtin_types() {
+    // Check that point! compiles for all built-in types
+    const _: Point<i8, 4> = point![0, 1, 2, 3];
+    const _: Point<i16, 4> = point![0, 1, 2, 3];
+    const _: Point<i32, 4> = point![0, 1, 2, 3];
+    const _: Point<i64, 4> = point![0, 1, 2, 3];
+    const _: Point<isize, 4> = point![0, 1, 2, 3];
+    const _: Point<u8, 4> = point![0, 1, 2, 3];
+    const _: Point<u16, 4> = point![0, 1, 2, 3];
+    const _: Point<u32, 4> = point![0, 1, 2, 3];
+    const _: Point<u64, 4> = point![0, 1, 2, 3];
+    const _: Point<usize, 4> = point![0, 1, 2, 3];
+    const _: Point<f32, 4> = point![0.0, 1.0, 2.0, 3.0];
+    const _: Point<f64, 4> = point![0.0, 1.0, 2.0, 3.0];
+}
+
 #[test]
 fn dvector_builtin_types() {
     // Check that dvector! compiles for all built-in types
@@ -248,6 +288,15 @@ fn vector_arbitrary_expressions() {
     assert_eq_and_type!(a, a_expected);
 }
 
+#[rustfmt::skip]
+#[test]
+fn point_arbitrary_expressions() {
+    // Test that point! supports arbitrary expressions for its elements
+    let a = point![1 + 2, 2 * 3, 4 * f(5 + 6), 7 - 8 * 9];
+    let a_expected = Point4::new(1 + 2, 2 * 3, 4 * f(5 + 6), 7 - 8 * 9);
+    assert_eq_and_type!(a, a_expected);
+}
+
 #[rustfmt::skip]
 #[test]
 fn dvector_arbitrary_expressions() {

src/lib.rs

@@ -137,7 +137,7 @@ pub use crate::sparse::*;
 pub use base as core;
 
 #[cfg(feature = "macros")]
-pub use nalgebra_macros::{dmatrix, dvector, matrix, vector};
+pub use nalgebra_macros::{dmatrix, dvector, matrix, point, vector};
 
 use simba::scalar::SupersetOf;
 use std::cmp::{self, Ordering, PartialOrd};

tests/core/macros.rs

@@ -1,11 +1,12 @@
-use nalgebra::{dmatrix, dvector, matrix, vector};
+use nalgebra::{dmatrix, dvector, matrix, point, vector};
 
 #[test]
 fn sanity_test() {
     // The macros are already tested in `nalgebra-macros`. Here we just test that they compile fine.
 
     let _ = matrix![1, 2, 3; 4, 5, 6];
     let _ = dmatrix![1, 2, 3; 4, 5, 6];
+    let _ = point![1, 2, 3, 4, 5, 6];
     let _ = vector![1, 2, 3, 4, 5, 6];
     let _ = dvector![1, 2, 3, 4, 5, 6];
 }