From df9c66d1bb5144dd08c1c19d75c0634f7a6df6e8 Mon Sep 17 00:00:00 2001
From: Brendan Zabarauskas <bjzaba@yahoo.com.au>
Date: Sat, 7 Sep 2013 19:51:01 +1000
Subject: [PATCH] Use macro instead of loop for Array::build

---
 src/cgmath/array.rs    | 16 +++++++++-------
 src/cgmath/matrix.rs   |  6 +++---
 src/cgmath/point.rs    |  4 ++--
 src/cgmath/rotation.rs |  2 +-
 src/cgmath/vector.rs   |  6 +++---
 5 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/src/cgmath/array.rs b/src/cgmath/array.rs
index 04ff408..5494fa5 100644
--- a/src/cgmath/array.rs
+++ b/src/cgmath/array.rs
@@ -53,7 +53,7 @@ pub trait Array
 }
 
 macro_rules! array(
-    (impl<$S:ident> $Self:ty -> [$T:ty, ..$n:expr]) => (
+    (impl<$S:ident> $Self:ty -> [$T:ty, ..$n:expr] $_n:ident) => (
         impl<$S: Clone> Array<$T, [$T,..$n]> for $Self {
             #[inline]
             fn i<'a>(&'a self, i: uint) -> &'a $T {
@@ -82,12 +82,7 @@ macro_rules! array(
 
             #[inline]
             fn build(builder: &fn(i: uint) -> $T) -> $Self {
-                use std::unstable::intrinsics;
-                let mut s: [$T,..$n] = unsafe { intrinsics::uninit() };
-                for i in range(0u, $n) {
-                    s[i] = builder(i);
-                }
-                Array::from_slice(s)
+                Array::from_slice(gen_builder!($_n))
             }
 
             #[inline]
@@ -103,6 +98,13 @@ macro_rules! array(
     )
 )
 
+macro_rules! gen_builder(
+    (_1) => ([builder(0)]);
+    (_2) => ([builder(0), builder(1)]);
+    (_3) => ([builder(0), builder(1), builder(2)]);
+    (_4) => ([builder(0), builder(1), builder(2), builder(3)]);
+)
+
 macro_rules! approx_eq(
     (impl<$S:ident> $Self:ty) => (
         impl<$S: Clone + ApproxEq<$S>> ApproxEq<$S> for $Self {
diff --git a/src/cgmath/matrix.rs b/src/cgmath/matrix.rs
index 0d12d46..7e20fd0 100644
--- a/src/cgmath/matrix.rs
+++ b/src/cgmath/matrix.rs
@@ -163,9 +163,9 @@ impl<S: Clone + Float> One for Mat2<S> { #[inline] fn one() -> Mat2<S> { Mat2::i
 impl<S: Clone + Float> One for Mat3<S> { #[inline] fn one() -> Mat3<S> { Mat3::ident() } }
 impl<S: Clone + Float> One for Mat4<S> { #[inline] fn one() -> Mat4<S> { Mat4::ident() } }
 
-array!(impl<S> Mat2<S> -> [Vec2<S>, ..2])
-array!(impl<S> Mat3<S> -> [Vec3<S>, ..3])
-array!(impl<S> Mat4<S> -> [Vec4<S>, ..4])
+array!(impl<S> Mat2<S> -> [Vec2<S>, ..2] _2)
+array!(impl<S> Mat3<S> -> [Vec3<S>, ..3] _3)
+array!(impl<S> Mat4<S> -> [Vec4<S>, ..4] _4)
 
 pub trait Matrix
 <
diff --git a/src/cgmath/point.rs b/src/cgmath/point.rs
index d447896..df9f1d7 100644
--- a/src/cgmath/point.rs
+++ b/src/cgmath/point.rs
@@ -76,8 +76,8 @@ pub trait Point
     #[inline] fn add_self_v(&mut self, other: &V) { for (a, b) in self.mut_iter().zip(other.iter()) { *a = a.add(b) } }
 }
 
-array!(impl<S> Point2<S> -> [S, ..2])
-array!(impl<S> Point3<S> -> [S, ..3])
+array!(impl<S> Point2<S> -> [S, ..2] _2)
+array!(impl<S> Point3<S> -> [S, ..3] _3)
 
 impl<S: Clone + Num + Ord> Point<S, Vec2<S>, [S, ..2]> for Point2<S>;
 impl<S: Clone + Num + Ord> Point<S, Vec3<S>, [S, ..3]> for Point3<S>;
diff --git a/src/cgmath/rotation.rs b/src/cgmath/rotation.rs
index 830a64f..22b4993 100644
--- a/src/cgmath/rotation.rs
+++ b/src/cgmath/rotation.rs
@@ -103,7 +103,7 @@ pub trait ToRot3<S: Clone + Float> {
 #[deriving(Eq, Clone)]
 pub struct Euler<A> { x: A, y: A, z: A }
 
-array!(impl<A> Euler<A> -> [A, ..3])
+array!(impl<A> Euler<A> -> [A, ..3] _3)
 
 pub trait ToEuler<A> {
     fn to_euler(&self) -> Euler<A>;
diff --git a/src/cgmath/vector.rs b/src/cgmath/vector.rs
index d5c6d0d..2f10772 100644
--- a/src/cgmath/vector.rs
+++ b/src/cgmath/vector.rs
@@ -83,9 +83,9 @@ impl<S: Clone + Num + Ord> Vec4<S> {
     #[inline] pub fn unit_w() -> Vec4<S> { Vec4::new(zero(), zero(), zero(), one()) }
 }
 
-array!(impl<S> Vec2<S> -> [S, ..2])
-array!(impl<S> Vec3<S> -> [S, ..3])
-array!(impl<S> Vec4<S> -> [S, ..4])
+array!(impl<S> Vec2<S> -> [S, ..2] _2)
+array!(impl<S> Vec3<S> -> [S, ..3] _3)
+array!(impl<S> Vec4<S> -> [S, ..4] _4)
 
 approx_eq!(impl<S> Vec2<S>)
 approx_eq!(impl<S> Vec3<S>)