Add XOr type and Filter::xor()

2 files changed, 33 insertions, 0 deletions

diff --git a/src/ops/mod.rs b/src/ops/mod.rs
index 668eedc..e5881af 100644
--- a/src/ops/mod.rs
+++ b/src/ops/mod.rs
@@ -1,3 +1,4 @@
 pub mod and;
 pub mod not;
 pub mod or;
+pub mod xor;
diff --git a/src/ops/xor.rs b/src/ops/xor.rs
new file mode 100644
index 0000000..42591d4
--- /dev/null
+++ b/src/ops/xor.rs
@@ -0,0 +1,32 @@
+//! XOR implementation.
+//!
+//! Will be automatically included when incluing `filter::Filter`, so importing this module
+//! shouldn't be necessary.
+//!
+use filter::Filter;
+
+#[must_use = "filters are lazy and do nothing unless consumed"]
+#[derive(Clone)]
+pub struct XOr<T, U> {
+    a: T,
+    b: U
+}
+
+impl<T, U> XOr<T, U> {
+
+    pub fn new(a: T, b: U) -> XOr<T, U> {
+        XOr { a: a, b: b }
+    }
+
+}
+
+impl<I, T: Filter<I>, U: Filter<I>> Filter<I> for XOr<T, U> {
+
+    fn filter(&self, e: &I) -> bool {
+        let a = self.a.filter(e);
+        let b = self.b.filter(e);
+
+        (a && !b) || (!a && b)
+    }
+
+}