1 files changed, 51 insertions, 0 deletions
diff --git a/src/ops/failable.rs b/src/ops/failable.rs
new file mode 100644
index 0000000..5a92ba7
--- /dev/null
+++ b/src/ops/failable.rs
@@ -0,0 +1,51 @@
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+//
+
+//! Filter -> FailableFilter implementations
+//!
+//! Will be automatically included when incluing `filter::Filter`, so importing this module
+//! shouldn't be necessary.
+//!
+use std::marker::PhantomData;
+
+use filter::Filter;
+use failable::filter::FailableFilter;
+
+#[must_use = "filters are lazy and do nothing unless consumed"]
+#[derive(Clone)]
+pub struct IntoFailable<F, E>(F, PhantomData<E>);
+
+impl<F, E> IntoFailable<F, E> {
+    pub fn new(a: F) -> IntoFailable<F, E> {
+        IntoFailable(a, PhantomData)
+    }
+}
+
+impl<F, N, E> FailableFilter<N, E> for IntoFailable<F, E>
+    where F: Filter<N>,
+{
+    fn filter(&self, e: &N) -> Result<bool, E> {
+        Ok(self.0.filter(e))
+    }
+}
+
+#[must_use = "filters are lazy and do nothing unless consumed"]
+#[derive(Clone)]
+pub struct AsFailable<'a, F: 'a + ?Sized, E>(&'a F, PhantomData<E>);
+
+impl<'a, F: 'a + ?Sized, E> AsFailable<'a, F, E> {
+    pub fn new(a: &'a F) -> AsFailable<F, E> {
+        AsFailable(a, PhantomData)
+    }
+}
+
+impl<'a, F, N, E> FailableFilter<N, E> for AsFailable<'a, F, E>
+    where F: Filter<N> + 'a + ?Sized,
+{
+    fn filter(&self, e: &N) -> Result<bool, E> {
+        Ok(self.0.filter(e))
+    }
+}