expose find_mut in the Map trait

src/libcore/container.rs

@@ -42,7 +42,7 @@ pub trait Map<K, V>: Mutable {
     fn find(&self, key: &K) -> Option<&'self V>;
 
     /// Return a mutable reference to the value corresponding to the key
-    //fn find_mut(&mut self, key: &K) -> Option<&'self mut V>;
+    fn find_mut(&mut self, key: &K) -> Option<&'self mut V>;
 
     /// Insert a key-value pair into the map. An existing value for a
     /// key is replaced by the new value. Return true if the key did

src/libcore/hashmap.rs

@@ -355,6 +355,17 @@ pub mod linear {
             }
         }
 
+        /// Return a mutable reference to the value corresponding to the key
+        fn find_mut(&mut self, k: &K) -> Option<&'self mut V> {
+            let idx = match self.bucket_for_key(k) {
+                FoundEntry(idx) => idx,
+                TableFull | FoundHole(_) => return None
+            };
+            unsafe {  // FIXME(#4903)---requires flow-sensitive borrow checker
+                Some(::cast::transmute_mut_region(self.mut_value_for_bucket(idx)))
+            }
+        }
+
         /// Insert a key-value pair into the map. An existing value for a
         /// key is replaced by the new value. Return true if the key did
         /// not already exist in the map.
@@ -419,17 +430,6 @@ pub mod linear {
             old_value
         }
 
-        /// Return a mutable reference to the value corresponding to the key
-        fn find_mut(&mut self, k: &K) -> Option<&'self mut V> {
-            let idx = match self.bucket_for_key(k) {
-                FoundEntry(idx) => idx,
-                TableFull | FoundHole(_) => return None
-            };
-            unsafe {  // FIXME(#4903)---requires flow-sensitive borrow checker
-                Some(::cast::transmute_mut_region(self.mut_value_for_bucket(idx)))
-            }
-        }
-
         /// Return the value corresponding to the key in the map, or insert
         /// and return the value if it doesn't exist.
         fn find_or_insert(&mut self, k: K, v: V) -> &'self V {

src/libcore/trie.rs

@@ -111,6 +111,12 @@ impl<T> Map<uint, T> for TrieMap<T> {
         }
     }
 
+    /// Return a mutable reference to the value corresponding to the key
+    #[inline(always)]
+    fn find_mut(&mut self, key: &uint) -> Option<&'self mut T> {
+        find_mut(&mut self.root.children[chunk(*key, 0)], *key, 1)
+    }
+
     /// Insert a key-value pair into the map. An existing value for a
     /// key is replaced by the new value. Return true if the key did
     /// not already exist in the map.
@@ -153,12 +159,6 @@ pub impl<T> TrieMap<T> {
     fn each_value_reverse(&self, f: &fn(&T) -> bool) {
         self.each_reverse(|&(_, v)| f(v))
     }
-
-    /// Return a mutable reference to the value corresponding to the key
-    #[inline(always)]
-    fn find_mut(&mut self, key: &uint) -> Option<&'self mut T> {
-        find_mut(&mut self.root.children[chunk(*key, 0)], *key, 1)
-    }
 }
 
 pub struct TrieSet {

src/libstd/smallintmap.rs

@@ -108,6 +108,18 @@ impl<V> Map<uint, V> for SmallIntMap<V> {
         }
     }
 
+    /// Return a mutable reference to the value corresponding to the key
+    fn find_mut(&mut self, key: &uint) -> Option<&'self mut V> {
+        if *key < self.v.len() {
+            match self.v[*key] {
+              Some(ref mut value) => Some(value),
+              None => None
+            }
+        } else {
+            None
+        }
+    }
+
     /// Insert a key-value pair into the map. An existing value for a
     /// key is replaced by the new value. Return true if the key did
     /// not already exist in the map.
@@ -140,18 +152,6 @@ pub impl<V> SmallIntMap<V> {
     fn get(&self, key: &uint) -> &'self V {
         self.find(key).expect("key not present")
     }
-
-    /// Return a mutable reference to the value corresponding to the key
-    fn find_mut(&mut self, key: &uint) -> Option<&'self mut V> {
-        if *key < self.v.len() {
-            match self.v[*key] {
-              Some(ref mut value) => Some(value),
-              None => None
-            }
-        } else {
-            None
-        }
-    }
 }
 
 pub impl<V:Copy> SmallIntMap<V> {

src/libstd/treemap.rs

@@ -152,6 +152,12 @@ impl<K: TotalOrd, V> Map<K, V> for TreeMap<K, V> {
         }
     }
 
+    /// Return a mutable reference to the value corresponding to the key
+    #[inline(always)]
+    fn find_mut(&mut self, key: &K) -> Option<&'self mut V> {
+        find_mut(&mut self.root, key)
+    }
+
     /// Insert a key-value pair into the map. An existing value for a
     /// key is replaced by the new value. Return true if the key did
     /// not already exist in the map.
@@ -189,12 +195,6 @@ pub impl<K: TotalOrd, V> TreeMap<K, V> {
     fn iter(&self) -> TreeMapIterator<'self, K, V> {
         TreeMapIterator{stack: ~[], node: &self.root}
     }
-
-    /// Return a mutable reference to the value corresponding to the key
-    #[inline(always)]
-    fn find_mut(&mut self, key: &K) -> Option<&'self mut V> {
-        find_mut(&mut self.root, key)
-    }
 }
 
 /// Lazy forward iterator over a map

src/test/run-pass/class-impl-very-parameterized-trait.rs

@@ -98,6 +98,8 @@ impl<T> Map<int, T> for cat<T> {
         }
     }
 
+    fn find_mut(&mut self, k: &int) -> Option<&'self mut T> { fail!() }
+
     fn remove(&mut self, k: &int) -> bool {
         if self.find(k).is_some() {
             self.meows -= *k; true