Merge accessors of fj::Difference2d

fj-operations/src/difference_2d.rs

@@ -16,8 +16,12 @@ impl ToShape for fj::Difference2d {
 
         let mut shape = Shape::new();
 
-        let [mut a, mut b] = [&self.a(), &self.b()]
-            .map(|shape| shape.to_shape(tolerance, debug_info));
+        // Can be cleaned up, once `each_ref` is stable:
+        // https://doc.rust-lang.org/std/primitive.array.html#method.each_ref
+        let [a, b] = self.shapes();
+        let shapes = [&a, &b];
+        let [mut a, mut b] =
+            shapes.map(|shape| shape.to_shape(tolerance, debug_info));
 
         // Check preconditions.
         //
@@ -76,7 +80,7 @@ impl ToShape for fj::Difference2d {
         // This is a conservative estimate of the bounding box: It's never going
         // to be bigger than the bounding box of the original shape that another
         // is being subtracted from.
-        self.a().bounding_volume()
+        self.shapes()[0].bounding_volume()
     }
 }
 

fj/src/shape_2d.rs

@@ -98,14 +98,9 @@ impl Difference2d {
         self.shapes[0].color()
     }
 
-    /// Access the original shape
-    pub fn a(&self) -> &Shape2d {
-        &self.shapes[0]
-    }
-
-    /// Access the shape being subtracted
-    pub fn b(&self) -> &Shape2d {
-        &self.shapes[1]
+    /// Access the shapes that make up the difference
+    pub fn shapes(&self) -> &[Shape2d; 2] {
+        &self.shapes
     }
 }