std: add result.map_move, result.map_err_move

3 files changed, 60 insertions, 12 deletions

diff --git a/src/libstd/local_data.rs b/src/libstd/local_data.rs
index c2a60e1c0e9..a73809d202c 100644
--- a/src/libstd/local_data.rs
+++ b/src/libstd/local_data.rs
@@ -110,16 +110,16 @@ fn test_tls_multitask() {
     set(my_key, @~"parent data");
     do task::spawn {
         // TLS shouldn't carry over.
-        assert!(get(my_key, |k| k.map(|&k| *k)).is_none());
+        assert!(get(my_key, |k| k.map_move(|k| *k)).is_none());
         set(my_key, @~"child data");
-        assert!(*(get(my_key, |k| k.map(|&k| *k)).unwrap()) ==
+        assert!(*(get(my_key, |k| k.map_move(|k| *k)).unwrap()) ==
                 ~"child data");
         // should be cleaned up for us
     }
     // Must work multiple times
-    assert!(*(get(my_key, |k| k.map(|&k| *k)).unwrap()) == ~"parent data");
-    assert!(*(get(my_key, |k| k.map(|&k| *k)).unwrap()) == ~"parent data");
-    assert!(*(get(my_key, |k| k.map(|&k| *k)).unwrap()) == ~"parent data");
+    assert!(*(get(my_key, |k| k.map_move(|k| *k)).unwrap()) == ~"parent data");
+    assert!(*(get(my_key, |k| k.map_move(|k| *k)).unwrap()) == ~"parent data");
+    assert!(*(get(my_key, |k| k.map_move(|k| *k)).unwrap()) == ~"parent data");
 }
 
 #[test]
@@ -127,7 +127,7 @@ fn test_tls_overwrite() {
     static my_key: Key<@~str> = &Key;
     set(my_key, @~"first data");
     set(my_key, @~"next data"); // Shouldn't leak.
-    assert!(*(get(my_key, |k| k.map(|&k| *k)).unwrap()) == ~"next data");
+    assert!(*(get(my_key, |k| k.map_move(|k| *k)).unwrap()) == ~"next data");
 }
 
 #[test]
diff --git a/src/libstd/result.rs b/src/libstd/result.rs
index 91f42edf0ae..e62ae3885eb 100644
--- a/src/libstd/result.rs
+++ b/src/libstd/result.rs
@@ -152,6 +152,40 @@ impl<T, E: ToStr> Result<T, E> {
     /// Call a method based on a previous result
     ///
     /// If `self` is `Ok` then the value is extracted and passed to `op`
+    /// whereupon `op`s result is wrapped in `Ok` and returned. if `self` is
+    /// `Err` then it is immediately returned.  This function can be used to
+    /// compose the results of two functions.
+    ///
+    /// Example:
+    ///
+    ///     let res = do read_file(file).map_move |buf| {
+    ///         parse_bytes(buf)
+    ///     }
+    #[inline]
+    pub fn map_move<U>(self, op: &fn(T) -> U) -> Result<U,E> {
+        match self {
+          Ok(t) => Ok(op(t)),
+          Err(e) => Err(e)
+        }
+    }
+
+    /// Call a method based on a previous result
+    ///
+    /// If `self` is `Err` then the value is extracted and passed to `op`
+    /// whereupon `op`s result is wrapped in an `Err` and returned. if `self` is
+    /// `Ok` then it is immediately returned.  This function can be used to pass
+    /// through a successful result while handling an error.
+    #[inline]
+    pub fn map_err_move<F>(self, op: &fn(E) -> F) -> Result<T,F> {
+        match self {
+          Ok(t) => Ok(t),
+          Err(e) => Err(op(e))
+        }
+    }
+
+    /// Call a method based on a previous result
+    ///
+    /// If `self` is `Ok` then the value is extracted and passed to `op`
     /// whereupon `op`s result is returned. if `self` is `Err` then it is
     /// immediately returned. This function can be used to compose the results
     /// of two functions.
@@ -312,7 +346,9 @@ pub fn iter_vec2<S, T, U: ToStr>(ss: &[S], ts: &[T],
 #[cfg(test)]
 mod tests {
     use super::*;
+
     use either;
+    use str::OwnedStr;
 
     pub fn op1() -> Result<int, ~str> { Ok(666) }
 
@@ -359,14 +395,26 @@ mod tests {
 
     #[test]
     pub fn test_impl_map() {
-        assert_eq!(Ok::<~str, ~str>(~"a").map(|_x| ~"b"), Ok(~"b"));
-        assert_eq!(Err::<~str, ~str>(~"a").map(|_x| ~"b"), Err(~"a"));
+        assert_eq!(Ok::<~str, ~str>(~"a").map(|x| (~"b").append(*x)), Ok(~"ba"));
+        assert_eq!(Err::<~str, ~str>(~"a").map(|x| (~"b").append(*x)), Err(~"a"));
     }
 
     #[test]
     pub fn test_impl_map_err() {
-        assert_eq!(Ok::<~str, ~str>(~"a").map_err(|_x| ~"b"), Ok(~"a"));
-        assert_eq!(Err::<~str, ~str>(~"a").map_err(|_x| ~"b"), Err(~"b"));
+        assert_eq!(Ok::<~str, ~str>(~"a").map_err(|x| (~"b").append(*x)), Ok(~"a"));
+        assert_eq!(Err::<~str, ~str>(~"a").map_err(|x| (~"b").append(*x)), Err(~"ba"));
+    }
+
+    #[test]
+    pub fn test_impl_map_move() {
+        assert_eq!(Ok::<~str, ~str>(~"a").map_move(|x| x + ~"b"), Ok(~"ab"));
+        assert_eq!(Err::<~str, ~str>(~"a").map_move(|x| x + ~"b"), Err(~"a"));
+    }
+
+    #[test]
+    pub fn test_impl_map_err_move() {
+        assert_eq!(Ok::<~str, ~str>(~"a").map_err_move(|x| x + ~"b"), Ok(~"a"));
+        assert_eq!(Err::<~str, ~str>(~"a").map_err_move(|x| x + ~"b"), Err(~"ab"));
     }
 
     #[test]
diff --git a/src/libstd/rt/task.rs b/src/libstd/rt/task.rs
index 4c5e4bdc3c1..e732ef67b5b 100644
--- a/src/libstd/rt/task.rs
+++ b/src/libstd/rt/task.rs
@@ -465,10 +465,10 @@ mod test {
         do run_in_newsched_task() {
             static key: local_data::Key<@~str> = &local_data::Key;
             local_data::set(key, @~"data");
-            assert!(*local_data::get(key, |k| k.map(|&k| *k)).unwrap() == ~"data");
+            assert!(*local_data::get(key, |k| k.map_move(|k| *k)).unwrap() == ~"data");
             static key2: local_data::Key<@~str> = &local_data::Key;
             local_data::set(key2, @~"data");
-            assert!(*local_data::get(key2, |k| k.map(|&k| *k)).unwrap() == ~"data");
+            assert!(*local_data::get(key2, |k| k.map_move(|k| *k)).unwrap() == ~"data");
         }
     }