From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Fri, 2 Apr 2021 21:16:24 +0000 (+0100)
Subject: geometry: Promote len2
X-Git-Tag: otter-0.5.0~301
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=commitdiff_plain;h=6af6c38f4035cbff21cc1db0983c20569139d2d7;p=otter.git

geometry: Promote len2

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/base/geometry.rs b/base/geometry.rs
index 4040207d..ab5527aa 100644
--- a/base/geometry.rs
+++ b/base/geometry.rs
@@ -104,6 +104,15 @@ impl<T> PosC<T> {
   pub fn zero() -> Self where T: num_traits::Zero + Copy {
     PosC::both(<T as num_traits::Zero>::zero())
   }
+
+  #[throws(CoordinateOverflow)]
+  pub fn len2(self) -> f64 where PosC<T>: PosPromote {
+    self.promote().coords.iter()
+      .try_fold(0., |b, &c| {
+        let c2 = c.checked_mul(c)?;
+        b.checked_add(c2)
+      })?
+  }
 }
 impl<T> PosC<T> where T: Copy {
   pub fn x(self) -> T { self.coords[0] }