nalgebra/src/core/constraint.rs

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use core::dimension::{Dim, DimName, Dynamic};
/// A type for enforcing constraints.
pub struct ShapeConstraint;
/// Constraints `C1` and `R2` to be equivalent.
pub trait AreMultipliable<R1: Dim, C1: Dim,
R2: Dim, C2: Dim> {
}
impl<R1: Dim, C1: Dim, R2: Dim, C2: Dim> AreMultipliable<R1, C1, R2, C2> for ShapeConstraint
where ShapeConstraint: DimEq<C1, R2> {
}
macro_rules! equality_trait_decl(
($($Trait: ident),* $(,)*) => {$(
// XXX: we can't do something like `DimEq<D1> for D2` because we would require a blancket impl…
pub trait $Trait<D1: Dim, D2: Dim> {
type Representative: Dim;
}
impl<D: Dim> $Trait<D, D> for ShapeConstraint {
type Representative = D;
}
impl<D: DimName> $Trait<D, Dynamic> for ShapeConstraint {
type Representative = D;
}
impl<D: DimName> $Trait<Dynamic, D> for ShapeConstraint {
type Representative = D;
}
)*}
);
equality_trait_decl!(DimEq, SameNumberOfRows, SameNumberOfColumns);
/// Constraints D1 and D2 to be equivalent, where the both designates dimensions of algebraic
/// entities (e.g. square matrices).
pub trait SameDimension<D1: Dim, D2: Dim>: SameNumberOfRows<D1, D2> + SameNumberOfColumns<D1, D2> {
type Representative: Dim;
}
impl<D: Dim> SameDimension<D, D> for ShapeConstraint {
type Representative = D;
}
impl<D: DimName> SameDimension<D, Dynamic> for ShapeConstraint {
type Representative = D;
}
impl<D: DimName> SameDimension<Dynamic, D> for ShapeConstraint {
type Representative = D;
}