From 9badebf24c78182801c8ef9c4e9f872be57f0c2e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Crozet?= <developer@crozet.re>
Date: Thu, 8 May 2014 23:19:42 +0200
Subject: [PATCH] Give access to the traits required for generalized operator
 overloading.

Those are `Vec3MulRhs`-like traits that allow the simulation of haskellish fundeps to allow multiple
overloads of builtin operators (* / + -).
They are all on the `na::overload` module.
---
 src/na.rs            | 28 ++++++++++++++++++++++++++++
 src/structs/metal.rs |  4 ++++
 src/structs/mod.rs   |  9 +++++++++
 3 files changed, 41 insertions(+)

diff --git a/src/na.rs b/src/na.rs
index 813647ab..98211927 100644
--- a/src/na.rs
+++ b/src/na.rs
@@ -52,6 +52,34 @@ pub use structs::{
     Vec0, Vec1, Vec2, Vec3, Vec4, Vec5, Vec6
 };
 
+/// Traits to work around the language limitations related to operator overloading.
+///
+/// The trait names are formed by:
+///
+/// * a type name (eg. Vec1, Vec2, Mat3, Mat4, etc.).
+/// * the name of a binary operation (eg. Mul, Div, Add, Sub, etc.). 
+/// * the word `Rhs`.
+///
+/// When implemented by the type `T`, the trait makes it possible to overload the binary operator
+/// between `T` and the type name given by the trait.
+///
+/// # Examples:
+///
+/// * `Vec3MulRhs` will allow the overload of the `*` operator between the implementor type and
+/// `Vec3`. The `Vec3` being the first argument of the multiplication.
+/// * `Mat4DivRhs` will allow the overload of the `/` operator between the implementor type and
+/// `Mat4`. The `Mat4` being the first argument of the division.
+pub mod overload {
+    pub use structs::{Vec1SubRhs, Vec2MulRhs, Vec3MulRhs, Vec4MulRhs, Vec5MulRhs, Vec6MulRhs,
+                      Vec1DivRhs, Vec2DivRhs, Vec3DivRhs, Vec4DivRhs, Vec5DivRhs, Vec6DivRhs,
+                      Vec1AddRhs, Vec2AddRhs, Vec3AddRhs, Vec4AddRhs, Vec5AddRhs, Vec6AddRhs,
+                      Vec1SubRhs, Vec2SubRhs, Vec3SubRhs, Vec4SubRhs, Vec5SubRhs, Vec6SubRhs,
+                      Mat1MulRhs, Mat2MulRhs, Mat3MulRhs, Mat4MulRhs, Mat5MulRhs, Mat6MulRhs,
+                      Mat1DivRhs, Mat2DivRhs, Mat3DivRhs, Mat4DivRhs, Mat5DivRhs, Mat6DivRhs,
+                      Mat1AddRhs, Mat2AddRhs, Mat3AddRhs, Mat4AddRhs, Mat5AddRhs, Mat6AddRhs,
+                      Mat1SubRhs, Mat2SubRhs, Mat3SubRhs, Mat4SubRhs, Mat5SubRhs, Mat6SubRhs};
+}
+
 /// Change the input value to ensure it is on the range `[min, max]`.
 #[inline(always)]
 pub fn clamp<T: Ord>(val: T, min: T, max: T) -> T {
diff --git a/src/structs/metal.rs b/src/structs/metal.rs
index c91d19d2..5e69c8c3 100644
--- a/src/structs/metal.rs
+++ b/src/structs/metal.rs
@@ -10,6 +10,10 @@
 macro_rules! double_dispatch_binop_decl_trait(
     ($t: ident, $trhs: ident) => (
         pub trait $trhs<N, Res> {
+            /// Applies the binary operation represented by this trait.
+            ///
+            /// In infix notation, assuming the operation is noted `*`, the following is computed:
+            /// `right * left`.
             fn binop(left: &$t<N>, right: &Self) -> Res;
         }
      )
diff --git a/src/structs/mod.rs b/src/structs/mod.rs
index e9c2935e..f7ebcac4 100644
--- a/src/structs/mod.rs
+++ b/src/structs/mod.rs
@@ -7,6 +7,15 @@ pub use self::mat::{Identity, Mat1, Mat2, Mat3, Mat4, Mat5, Mat6};
 pub use self::rot::{Rot2, Rot3, Rot4};
 pub use self::iso::{Iso2, Iso3, Iso4};
 
+pub use self::vec::{Vec1MulRhs, Vec2MulRhs, Vec3MulRhs, Vec4MulRhs, Vec5MulRhs, Vec6MulRhs,
+                    Vec1DivRhs, Vec2DivRhs, Vec3DivRhs, Vec4DivRhs, Vec5DivRhs, Vec6DivRhs,
+                    Vec1AddRhs, Vec2AddRhs, Vec3AddRhs, Vec4AddRhs, Vec5AddRhs, Vec6AddRhs,
+                    Vec1SubRhs, Vec2SubRhs, Vec3SubRhs, Vec4SubRhs, Vec5SubRhs, Vec6SubRhs};
+pub use self::mat::{Mat1MulRhs, Mat2MulRhs, Mat3MulRhs, Mat4MulRhs, Mat5MulRhs, Mat6MulRhs,
+                    Mat1DivRhs, Mat2DivRhs, Mat3DivRhs, Mat4DivRhs, Mat5DivRhs, Mat6DivRhs,
+                    Mat1AddRhs, Mat2AddRhs, Mat3AddRhs, Mat4AddRhs, Mat5AddRhs, Mat6AddRhs,
+                    Mat1SubRhs, Mat2SubRhs, Mat3SubRhs, Mat4SubRhs, Mat5SubRhs, Mat6SubRhs};
+
 mod dmat;
 mod dvec;
 mod vec;