Split up some files

1 files changed, 81 insertions, 0 deletions

diff --git a/src/model/fold.rs b/src/model/fold.rs
new file mode 100644
index 00000000..bc85be01
--- /dev/null
+++ b/src/model/fold.rs
@@ -0,0 +1,81 @@
+use super::Smart;
+use crate::geom::{Abs, Corners, Length, Rel, Sides};
+
+/// A property that is folded to determine its final value.
+pub trait Fold {
+    /// The type of the folded output.
+    type Output;
+
+    /// Fold this inner value with an outer folded value.
+    fn fold(self, outer: Self::Output) -> Self::Output;
+}
+
+impl<T> Fold for Option<T>
+where
+    T: Fold,
+    T::Output: Default,
+{
+    type Output = Option<T::Output>;
+
+    fn fold(self, outer: Self::Output) -> Self::Output {
+        self.map(|inner| inner.fold(outer.unwrap_or_default()))
+    }
+}
+
+impl<T> Fold for Smart<T>
+where
+    T: Fold,
+    T::Output: Default,
+{
+    type Output = Smart<T::Output>;
+
+    fn fold(self, outer: Self::Output) -> Self::Output {
+        self.map(|inner| inner.fold(outer.unwrap_or_default()))
+    }
+}
+
+impl<T> Fold for Sides<T>
+where
+    T: Fold,
+{
+    type Output = Sides<T::Output>;
+
+    fn fold(self, outer: Self::Output) -> Self::Output {
+        self.zip(outer, |inner, outer| inner.fold(outer))
+    }
+}
+
+impl Fold for Sides<Option<Rel<Abs>>> {
+    type Output = Sides<Rel<Abs>>;
+
+    fn fold(self, outer: Self::Output) -> Self::Output {
+        self.zip(outer, |inner, outer| inner.unwrap_or(outer))
+    }
+}
+
+impl Fold for Sides<Option<Smart<Rel<Length>>>> {
+    type Output = Sides<Smart<Rel<Length>>>;
+
+    fn fold(self, outer: Self::Output) -> Self::Output {
+        self.zip(outer, |inner, outer| inner.unwrap_or(outer))
+    }
+}
+
+impl<T> Fold for Corners<T>
+where
+    T: Fold,
+{
+    type Output = Corners<T::Output>;
+
+    fn fold(self, outer: Self::Output) -> Self::Output {
+        self.zip(outer, |inner, outer| inner.fold(outer))
+    }
+}
+
+impl Fold for Corners<Option<Rel<Abs>>> {
+    type Output = Corners<Rel<Abs>>;
+
+    fn fold(self, outer: Self::Output) -> Self::Output {
+        self.zip(outer, |inner, outer| inner.unwrap_or(outer))
+    }
+}