Optimize negabs (#962)

* Optimize negabs

* Keep this for another PR

* cargo fmt

* Fix brackets in value_mon_impl macro

* Can't use [] for Complex, result is real

Author: lynn

src/algorithm/pervade.rs

@@ -1242,6 +1242,34 @@ pub mod square_abs {
     }
 }
 
+pub mod neg_abs {
+    use super::*;
+    pub fn num(a: f64) -> f64 {
+        -a.abs()
+    }
+    pub fn byte(a: u8) -> f64 {
+        -f64::from(a)
+    }
+    pub fn char(a: char) -> char {
+        if a.is_uppercase() {
+            let mut upper = a.to_lowercase();
+            if upper.len() == 1 {
+                upper.next().unwrap()
+            } else {
+                a
+            }
+        } else {
+            a
+        }
+    }
+    pub fn com(a: Complex) -> f64 {
+        -a.abs()
+    }
+    pub fn error<T: Display>(a: T, env: &Uiua) -> UiuaError {
+        env.error(format!("Cannot take the absolute value of {a}"))
+    }
+}
+
 macro_rules! eq_impl {
     ($name:ident $eq:tt $ordering:expr) => {
         pub mod $name {

src/compile/optimize.rs

@@ -128,7 +128,8 @@ static UNSORTED_OPTS: &[&dyn Optimization] = &[
     &((3, Pow), (Dup, Dup, Mul, Mul)),
     &((4, Pow), (Dup, Mul, Dup, Mul)),
     &((Complex, Abs), AbsComplex),
-    &((Abs, Dup, Mul), (SquareAbs)),
+    &((Abs, Dup, Mul), SquareAbs),
+    &((Abs, Neg), NegAbs),
     &ByToDup,
     &RowsFlipOpt,
     &InlineCustomInverse,

src/impl_prim.rs

@@ -242,6 +242,7 @@ impl_primitive!(
     (2[1], SplitByKeepEmpty),
     (2, AbsComplex),
     (1, SquareAbs),
+    (1, NegAbs),
     (2, MatrixDiv),
     (1, RangeSub(i32)),
     (1, Exp2),

src/run_prim.rs

@@ -1011,6 +1011,7 @@ impl ImplPrimitive {
             // Optimizations
             ImplPrimitive::AbsComplex => env.dyadic_oo_env(Value::abs_complex)?,
             ImplPrimitive::SquareAbs => env.monadic_env(Value::square_abs)?,
+            ImplPrimitive::NegAbs => env.monadic_env(Value::neg_abs)?,
             ImplPrimitive::FirstMinIndex => env.monadic_ref_env(Value::first_min_index)?,
             ImplPrimitive::FirstMaxIndex => env.monadic_ref_env(Value::first_max_index)?,
             ImplPrimitive::LastMinIndex => env.monadic_ref_env(Value::last_min_index)?,

src/value.rs

@@ -1805,6 +1805,13 @@ value_mon_impl!(exp10, [Num, num], (Byte, byte), [Complex, com]);
 value_mon_impl!(log2, [Num, num], (Byte, byte), [Complex, com]);
 value_mon_impl!(log10, [Num, num], (Byte, byte), [Complex, com]);
 value_mon_impl!(square_abs, [Num, num], (Byte, byte), (Complex, com));
+value_mon_impl!(
+    neg_abs,
+    [Num, num],
+    (Byte, byte),
+    (Complex, com),
+    [Char, char]
+);
 
 impl Value {
     /// Get the `absolute value` of a value