Merge pull request #311 from hannobraun/diff

Clean up 2D difference code

src/kernel/shapes/difference_2d.rs

@@ -16,20 +16,11 @@ impl ToShape for fj::Difference2d {
 
         let mut shape = Shape::new();
 
-        let mut a = self.a.to_shape(tolerance, debug_info);
+        let [mut a, mut b] = [&self.a, &self.b]
-        let mut b = self.b.to_shape(tolerance, debug_info);
+            .map(|shape| shape.to_shape(tolerance, debug_info));
 
-        if a.cycles().all().count() == 1 && b.cycles().all().count() == 1 {
+        for shape in [&mut a, &mut b] {
-            let a = a.cycles().all().next().unwrap();
+            if shape.cycles().all().count() != 1 {
-            let b = b.cycles().all().next().unwrap();
-
-            shape.cycles().add(Cycle {
-                edges: a.edges.clone(),
-            });
-            shape.cycles().add(Cycle {
-                edges: b.edges.clone(),
-            });
-        } else {
                 // See issue:
                 // https://github.com/hannobraun/Fornjot/issues/95
                 todo!(
@@ -37,27 +28,32 @@ impl ToShape for fj::Difference2d {
                     cycle in each operand."
                 );
             }
-
+            if shape.faces().all().count() != 1 {
-        {
-            let (a, b) = if a.faces().all().count() == 1
-                && b.faces().all().count() == 1
-            {
-                // Can't panic. We just checked that length of `a` and `b` is 1.
-                (
-                    a.faces().all().next().unwrap(),
-                    b.faces().all().next().unwrap(),
-                )
-            } else {
                 // See issue:
                 // https://github.com/hannobraun/Fornjot/issues/95
                 todo!(
                     "The 2-dimensional difference operation only supports one \
                     face in each operand."
                 );
-            };
+            }
+        }
 
-            let (a, b, surface_a, surface_b) =
+        // Can't panic, as we just verified that both shapes have one cycle.
-                match ((*a).clone(), (*b).clone()) {
+        let cycles =
+            [&mut a, &mut b].map(|shape| shape.cycles().all().next().unwrap());
+
+        for cycle in cycles {
+            shape.cycles().add(Cycle {
+                edges: cycle.edges.clone(),
+            });
+        }
+
+        // Can't panic, as we just verified that both shapes have one face.
+        let [face_a, face_b] =
+            [&mut a, &mut b].map(|shape| shape.faces().all().next().unwrap());
+
+        let (cycles_a, cycles_b, surface_a, surface_b) =
+            match ((*face_a).clone(), (*face_b).clone()) {
                 (
                     Face::Face {
                         cycles: a,
@@ -69,25 +65,21 @@ impl ToShape for fj::Difference2d {
                     },
                 ) => (a, b, surface_a, surface_b),
                 _ => {
-                        // None of the 2D types still use triangle
+                    // None of the 2D types still use triangle representation.
-                        // representation.
                     unreachable!()
                 }
             };
 
         assert!(
             surface_a == surface_b,
-                // Panicking is not great, but as long as we don't have a real
-                // error handling mechanism, it will do.
             "Trying to subtract sketches with different surfaces."
         );
         let surface = surface_a;
 
-            let mut cycles = a;
+        let mut cycles = cycles_a;
-            cycles.extend(b);
+        cycles.extend(cycles_b);
 
         shape.faces().add(Face::Face { cycles, surface });
-        };
 
         shape
     }