added map_x and while_ok

3 files changed, 190 insertions, 0 deletions

diff --git a/src/lib.rs b/src/lib.rs
index f8fb768..d949faa 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -109,10 +109,12 @@
 //!
 
 pub mod errors;
+pub mod map_x;
 pub mod oks;
 pub mod onerr;
 pub mod onok;
 pub mod prelude;
 pub mod unwrap;
+pub mod while_ok;
 mod util;
 
diff --git a/src/map_x.rs b/src/map_x.rs
new file mode 100644
index 0000000..a328dd1
--- /dev/null
+++ b/src/map_x.rs
@@ -0,0 +1,131 @@
+//
+// 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/.
+//
+
+/// Extension trait for `Iterator<Item = Result<O, E>>` to iter until an error is encountered.
+pub trait MapX<O, E> : Sized
+{
+    fn map_ok<F, O2>(self, F) -> MapOk<Self, F>
+        where F: FnMut(O) -> O2;
+    fn map_err<F, E2>(self, F) -> MapErr<Self, F>
+        where F: FnMut(E) -> E2;
+}
+
+impl<I, O, E> MapX<O, E> for I
+    where I: Iterator<Item = Result<O, E>> + Sized,
+{
+    fn map_ok<F, O2>(self, f: F) -> MapOk<Self, F>
+        where F: FnMut(O) -> O2
+    {
+        MapOk{ iter: self, f }
+    }
+    fn map_err<F, E2>(self, f: F) -> MapErr<Self, F>
+        where F: FnMut(E) -> E2
+    {
+        MapErr{ iter: self, f }
+    }
+}
+
+
+#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
+pub struct MapOk<I, F> {
+    iter: I,
+    f: F,
+}
+
+impl<I, O, E, F, O2> Iterator for MapOk<I, F>
+    where I: Iterator<Item = Result<O, E>>,
+          F: FnMut(O) -> O2,
+{
+    type Item = Result<O2, E>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.iter.next().map(|r| r.map(&mut self.f))
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+}
+
+
+#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
+pub struct MapErr<I, F> {
+    iter: I,
+    f: F,
+}
+
+impl<I, O, E, F, E2> Iterator for MapErr<I, F>
+    where I: Iterator<Item = Result<O, E>>,
+          F: FnMut(E) -> E2,
+{
+    type Item = Result<O, E2>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.iter.next().map(|r| r.map_err(&mut self.f))
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+}
+
+
+#[test]
+fn test_map_ok() {
+    use std::str::FromStr;
+
+    let mapped: Vec<_> = ["1", "2", "a", "4", "5"]
+        .into_iter()
+        .map(|txt| usize::from_str(txt))
+        .map_ok(|i| 2*i)
+        .collect();
+
+    assert_eq!(mapped[0], Ok(2));
+    assert_eq!(mapped[1], Ok(4));
+    assert_eq!(mapped[3], Ok(8));
+    assert_eq!(mapped[4], Ok(10));
+}
+
+#[test]
+fn test_map_ok_hint() {
+    use std::str::FromStr;
+
+    let hint = ["1", "2", "a", "4", "5"]
+        .into_iter()
+        .map(|txt| usize::from_str(txt))
+        .map_ok(|i| 2*i)
+        .size_hint();
+
+    assert_eq!(hint, (5, Some(5)));
+}
+
+#[test]
+fn test_map_err() {
+    use std::str::FromStr;
+
+    let mapped: Vec<_> = ["1", "2", "a", "4", "5"]
+        .into_iter()
+        .map(|txt| usize::from_str(txt))
+        .map_err(|e| format!("{:?}", e))
+        .collect();
+
+    assert_eq!(mapped[2], Err("ParseIntError { kind: InvalidDigit }".to_string()));
+}
+
+#[test]
+fn test_map_err_hint() {
+    use std::str::FromStr;
+
+    let hint = ["1", "2", "a", "4", "5"]
+        .into_iter()
+        .map(|txt| usize::from_str(txt))
+        .map_err(|e| format!("{:?}", e))
+        .size_hint();
+
+    assert_eq!(hint, (5, Some(5)));
+}
diff --git a/src/while_ok.rs b/src/while_ok.rs
new file mode 100644
index 0000000..ef5c03f
--- /dev/null
+++ b/src/while_ok.rs
@@ -0,0 +1,57 @@
+//
+// 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/.
+//
+
+/// Extension trait for `Iterator<Item = Result<O, E>>` to iter until an error is encountered.
+pub trait WhileOk<O, E>
+{
+    fn while_ok<F>(self, F) -> Result<(), E>
+        where F: FnMut(O) -> ();
+}
+
+impl<I, O, E> WhileOk<O, E> for I
+    where I: Iterator<Item = Result<O, E>>,
+{
+    fn while_ok<F>(self, mut f: F) -> Result<(), E>
+        where F: FnMut(O) -> ()
+    {
+        for res in self {
+            f(res?);
+        }
+        Ok(())
+    }
+}
+
+
+
+#[test]
+fn test_while_ok_ok() {
+    use std::str::FromStr;
+
+    let mut s = 0;
+
+    let res = ["1", "2", "3", "4", "5"]
+        .into_iter()
+        .map(|txt| usize::from_str(txt))
+        .while_ok(|i| s += i);
+
+    assert_eq!(s, 15);
+    assert!(res.is_ok());
+}
+
+#[test]
+fn test_while_ok_err() {
+    use std::str::FromStr;
+
+    let mut s = 0;
+
+    let res = ["1", "2", "a", "4", "5"]
+        .into_iter()
+        .map(|txt| usize::from_str(txt))
+        .while_ok(|i| s += i);
+
+    assert_eq!(s, 3);
+    assert!(res.is_err());
+}