From 19e35d3b9e58555f27b170920ce5ce9c553ce5b2 Mon Sep 17 00:00:00 2001
From: Jim Turner <github@turner.link>
Date: Sat, 15 Feb 2020 15:15:06 -0500
Subject: [PATCH] Generalize lhs scalar ops to more combos of types

This doesn't have a noticeable impact on the results of the
`scalar_add_2` and `scalar_add_strided_2` benchmarks.
---
 src/impl_ops.rs | 134 ++++++++++++++++++++++--------------------------
 1 file changed, 60 insertions(+), 74 deletions(-)

diff --git a/src/impl_ops.rs b/src/impl_ops.rs
index 5e57d610e..8999999f1 100644
--- a/src/impl_ops.rs
+++ b/src/impl_ops.rs
@@ -166,56 +166,42 @@ impl<'a, A, S, D, B, C> $trt<B> for &'a ArrayBase<S, D>
     );
 );
 
-// Pick the expression $a for commutative and $b for ordered binop
-macro_rules! if_commutative {
-    (Commute { $a:expr } or { $b:expr }) => {
-        $a
-    };
-    (Ordered { $a:expr } or { $b:expr }) => {
-        $b
-    };
-}
-
 macro_rules! impl_scalar_lhs_op {
-    // $commutative flag. Reuse the self + scalar impl if we can.
-    // We can do this safely since these are the primitive numeric types
-    ($scalar:ty, $commutative:ident, $operator:tt, $trt:ident, $mth:ident, $doc:expr) => (
-// these have no doc -- they are not visible in rustdoc
-// Perform elementwise
-// between the scalar `self` and array `rhs`,
-// and return the result (based on `self`).
-impl<S, D> $trt<ArrayBase<S, D>> for $scalar
-    where S: DataOwned<Elem=$scalar> + DataMut,
-          D: Dimension,
+    ($scalar:ty, $operator:tt, $trt:ident, $mth:ident, $doc:expr) => (
+/// Perform elementwise
+#[doc=$doc]
+/// between the scalar `self` and array `rhs`,
+/// and return the result (based on `self`).
+impl<A, S, D> $trt<ArrayBase<S, D>> for $scalar
+where
+    $scalar: Clone + $trt<A, Output=A>,
+    A: Clone,
+    S: DataOwned<Elem=A> + DataMut,
+    D: Dimension,
 {
     type Output = ArrayBase<S, D>;
-    fn $mth(self, rhs: ArrayBase<S, D>) -> ArrayBase<S, D> {
-        if_commutative!($commutative {
-            rhs.$mth(self)
-        } or {{
-            let mut rhs = rhs;
-            rhs.unordered_foreach_mut(move |elt| {
-                *elt = self $operator *elt;
-            });
-            rhs
-        }})
+    fn $mth(self, mut rhs: ArrayBase<S, D>) -> ArrayBase<S, D> {
+        rhs.unordered_foreach_mut(move |elt| {
+            *elt = self.clone() $operator elt.clone();
+        });
+        rhs
     }
 }
 
-// Perform elementwise
-// between the scalar `self` and array `rhs`,
-// and return the result as a new `Array`.
-impl<'a, S, D> $trt<&'a ArrayBase<S, D>> for $scalar
-    where S: Data<Elem=$scalar>,
-          D: Dimension,
+/// Perform elementwise
+#[doc=$doc]
+/// between the scalar `self` and array `rhs`,
+/// and return the result as a new `Array`.
+impl<'a, A, S, D, B> $trt<&'a ArrayBase<S, D>> for $scalar
+where
+      $scalar: Clone + $trt<A, Output=B>,
+      A: Clone,
+      S: Data<Elem=A>,
+      D: Dimension,
 {
-    type Output = Array<$scalar, D>;
-    fn $mth(self, rhs: &ArrayBase<S, D>) -> Array<$scalar, D> {
-        if_commutative!($commutative {
-            rhs.$mth(self)
-        } or {
-            self.$mth(rhs.to_owned())
-        })
+    type Output = Array<B, D>;
+    fn $mth(self, rhs: &ArrayBase<S, D>) -> Array<B, D> {
+        rhs.map(move |elt| self.clone() $operator elt.clone())
     }
 }
     );
@@ -241,16 +227,16 @@ mod arithmetic_ops {
 
     macro_rules! all_scalar_ops {
         ($int_scalar:ty) => (
-            impl_scalar_lhs_op!($int_scalar, Commute, +, Add, add, "addition");
-            impl_scalar_lhs_op!($int_scalar, Ordered, -, Sub, sub, "subtraction");
-            impl_scalar_lhs_op!($int_scalar, Commute, *, Mul, mul, "multiplication");
-            impl_scalar_lhs_op!($int_scalar, Ordered, /, Div, div, "division");
-            impl_scalar_lhs_op!($int_scalar, Ordered, %, Rem, rem, "remainder");
-            impl_scalar_lhs_op!($int_scalar, Commute, &, BitAnd, bitand, "bit and");
-            impl_scalar_lhs_op!($int_scalar, Commute, |, BitOr, bitor, "bit or");
-            impl_scalar_lhs_op!($int_scalar, Commute, ^, BitXor, bitxor, "bit xor");
-            impl_scalar_lhs_op!($int_scalar, Ordered, <<, Shl, shl, "left shift");
-            impl_scalar_lhs_op!($int_scalar, Ordered, >>, Shr, shr, "right shift");
+            impl_scalar_lhs_op!($int_scalar, +, Add, add, "addition");
+            impl_scalar_lhs_op!($int_scalar, -, Sub, sub, "subtraction");
+            impl_scalar_lhs_op!($int_scalar, *, Mul, mul, "multiplication");
+            impl_scalar_lhs_op!($int_scalar, /, Div, div, "division");
+            impl_scalar_lhs_op!($int_scalar, %, Rem, rem, "remainder");
+            impl_scalar_lhs_op!($int_scalar, &, BitAnd, bitand, "bit and");
+            impl_scalar_lhs_op!($int_scalar, |, BitOr, bitor, "bit or");
+            impl_scalar_lhs_op!($int_scalar, ^, BitXor, bitxor, "bit xor");
+            impl_scalar_lhs_op!($int_scalar, <<, Shl, shl, "left shift");
+            impl_scalar_lhs_op!($int_scalar, >>, Shr, shr, "right shift");
         );
     }
     all_scalar_ops!(i8);
@@ -264,31 +250,31 @@ mod arithmetic_ops {
     all_scalar_ops!(i128);
     all_scalar_ops!(u128);
 
-    impl_scalar_lhs_op!(bool, Commute, &, BitAnd, bitand, "bit and");
-    impl_scalar_lhs_op!(bool, Commute, |, BitOr, bitor, "bit or");
-    impl_scalar_lhs_op!(bool, Commute, ^, BitXor, bitxor, "bit xor");
+    impl_scalar_lhs_op!(bool, &, BitAnd, bitand, "bit and");
+    impl_scalar_lhs_op!(bool, |, BitOr, bitor, "bit or");
+    impl_scalar_lhs_op!(bool, ^, BitXor, bitxor, "bit xor");
 
-    impl_scalar_lhs_op!(f32, Commute, +, Add, add, "addition");
-    impl_scalar_lhs_op!(f32, Ordered, -, Sub, sub, "subtraction");
-    impl_scalar_lhs_op!(f32, Commute, *, Mul, mul, "multiplication");
-    impl_scalar_lhs_op!(f32, Ordered, /, Div, div, "division");
-    impl_scalar_lhs_op!(f32, Ordered, %, Rem, rem, "remainder");
+    impl_scalar_lhs_op!(f32, +, Add, add, "addition");
+    impl_scalar_lhs_op!(f32, -, Sub, sub, "subtraction");
+    impl_scalar_lhs_op!(f32, *, Mul, mul, "multiplication");
+    impl_scalar_lhs_op!(f32, /, Div, div, "division");
+    impl_scalar_lhs_op!(f32, %, Rem, rem, "remainder");
 
-    impl_scalar_lhs_op!(f64, Commute, +, Add, add, "addition");
-    impl_scalar_lhs_op!(f64, Ordered, -, Sub, sub, "subtraction");
-    impl_scalar_lhs_op!(f64, Commute, *, Mul, mul, "multiplication");
-    impl_scalar_lhs_op!(f64, Ordered, /, Div, div, "division");
-    impl_scalar_lhs_op!(f64, Ordered, %, Rem, rem, "remainder");
+    impl_scalar_lhs_op!(f64, +, Add, add, "addition");
+    impl_scalar_lhs_op!(f64, -, Sub, sub, "subtraction");
+    impl_scalar_lhs_op!(f64, *, Mul, mul, "multiplication");
+    impl_scalar_lhs_op!(f64, /, Div, div, "division");
+    impl_scalar_lhs_op!(f64, %, Rem, rem, "remainder");
 
-    impl_scalar_lhs_op!(Complex<f32>, Commute, +, Add, add, "addition");
-    impl_scalar_lhs_op!(Complex<f32>, Ordered, -, Sub, sub, "subtraction");
-    impl_scalar_lhs_op!(Complex<f32>, Commute, *, Mul, mul, "multiplication");
-    impl_scalar_lhs_op!(Complex<f32>, Ordered, /, Div, div, "division");
+    impl_scalar_lhs_op!(Complex<f32>, +, Add, add, "addition");
+    impl_scalar_lhs_op!(Complex<f32>, -, Sub, sub, "subtraction");
+    impl_scalar_lhs_op!(Complex<f32>, *, Mul, mul, "multiplication");
+    impl_scalar_lhs_op!(Complex<f32>, /, Div, div, "division");
 
-    impl_scalar_lhs_op!(Complex<f64>, Commute, +, Add, add, "addition");
-    impl_scalar_lhs_op!(Complex<f64>, Ordered, -, Sub, sub, "subtraction");
-    impl_scalar_lhs_op!(Complex<f64>, Commute, *, Mul, mul, "multiplication");
-    impl_scalar_lhs_op!(Complex<f64>, Ordered, /, Div, div, "division");
+    impl_scalar_lhs_op!(Complex<f64>, +, Add, add, "addition");
+    impl_scalar_lhs_op!(Complex<f64>, -, Sub, sub, "subtraction");
+    impl_scalar_lhs_op!(Complex<f64>, *, Mul, mul, "multiplication");
+    impl_scalar_lhs_op!(Complex<f64>, /, Div, div, "division");
 
     impl<A, S, D> Neg for ArrayBase<S, D>
     where