Merge pull request #642 from Marcos-cat/unity

experimental negate subscripts as roots of unity
uiua-lang · Dec 31, 2024 · 7f140b7 · 7f140b7
2 parents a7e5534 + 62fb0f8
commit 7f140b7
Show file tree

Hide file tree

Showing 2 changed files with 25 additions and 0 deletions.
diff --git a/src/compile/mod.rs b/src/compile/mod.rs
@@ -2055,6 +2055,24 @@ code:
                             .map(|_| self.primitive(prim, span.clone()))
                             .collect()
                     }
+                    Primitive::Neg => {
+                        self.subscript_experimental(prim, &span);
+                        if n == 0 {
+                            self.add_error(span.clone(), "Cannot have the 0th root of unity");
+                        }
+                        // Ensure that common cases are exact
+                        let root_of_unity = match n {
+                            1 | -1 => crate::Complex::ONE,
+                            2 | -2 => -crate::Complex::ONE,
+                            4 => crate::Complex::I,
+                            -4 => -crate::Complex::I,
+                            _ => (crate::Complex::I * (std::f64::consts::TAU / n as f64)).exp(),
+                        };
+                        Node::from_iter([
+                            Node::new_push(root_of_unity),
+                            self.primitive(Primitive::Mul, span),
+                        ])
+                    }
                     Primitive::Sqrt => {
                         if n == 0 {
                             self.add_error(span.clone(), "Cannot take 0th root");

diff --git a/tests/optimized.ua b/tests/optimized.ua
@@ -252,3 +252,10 @@ F ← ⬚10(/+◌1⊞(×¯))
 ⍤⤙≍ ⊃⧅≥⧅(∘≥) 4 ⇡3
 ⍤⤙≍ ⊃⧅≠⧅(∘≠) ¯1 ⇡4
 ⍤⤙≍ ⊃⧅<⧅(∘<) ¯1 ⇡4
+
+# Experimental!
+⍤⤙≍ ℂ5 0 ¯₄ 5
+⍤⤙≍ ℂ¯π 0 °¯₄ π
+⍤⤙≍ ℂ0 5 ⁅₁₀ ⍥₃¯₃ 5
+⍤⤙≍ ℂ0 5 ⁅₁₀ ⍥₃¯₋₃ 5
+⍤⤙≍ ℂ0 5 ⁅₁₀ ⍥₇¯₇ 5