add intersection and union to the Set trait

Author: thestinger

src/libcore/container.rs

@@ -81,4 +81,10 @@ pub trait Set<T>: Mutable {
 
     /// Visit the values representing the symmetric difference
     pure fn symmetric_difference(&self, other: &self, f: fn(&T) -> bool);
+
+    /// Visit the values representing the intersection
+    pure fn intersection(&self, other: &self, f: fn(&T) -> bool);
+
+    /// Visit the values representing the union
+    pure fn union(&self, other: &self, f: fn(&T) -> bool);
 }

src/libcore/hashmap.rs

@@ -474,7 +474,7 @@ pub mod linear {
         pure fn difference(&self, other: &LinearSet<T>, f: fn(&T) -> bool) {
             for self.each |v| {
                 if !other.contains(v) {
-                    if !f(v) { return; }
+                    if !f(v) { return }
                 }
             }
         }
@@ -485,6 +485,28 @@ pub mod linear {
             self.difference(other, f);
             other.difference(self, f);
         }
+
+        /// Visit the values representing the intersection
+        pure fn intersection(&self, other: &LinearSet<T>, f: fn(&T) -> bool) {
+            for self.each |v| {
+                if other.contains(v) {
+                    if !f(v) { return }
+                }
+            }
+        }
+
+        /// Visit the values representing the union
+        pure fn union(&self, other: &LinearSet<T>, f: fn(&T) -> bool) {
+            for self.each |v| {
+                if !f(v) { return }
+            }
+
+            for other.each |v| {
+                if !self.contains(v) {
+                    if !f(v) { return }
+                }
+            }
+        }
     }
 
     pub impl <T: Hash IterBytes Eq> LinearSet<T> {
@@ -698,6 +720,36 @@ mod test_set {
         assert b.is_superset(&a);
     }
 
+    #[test]
+    fn test_intersection() {
+        let mut a = linear::LinearSet::new();
+        let mut b = linear::LinearSet::new();
+
+        assert a.insert(11);
+        assert a.insert(1);
+        assert a.insert(3);
+        assert a.insert(77);
+        assert a.insert(103);
+        assert a.insert(5);
+        assert a.insert(-5);
+
+        assert b.insert(2);
+        assert b.insert(11);
+        assert b.insert(77);
+        assert b.insert(-9);
+        assert b.insert(-42);
+        assert b.insert(5);
+        assert b.insert(3);
+
+        let mut i = 0;
+        let expected = [3, 5, 11, 77];
+        for a.intersection(&b) |x| {
+            assert vec::contains(expected, x);
+            i += 1
+        }
+        assert i == expected.len();
+    }
+
     #[test]
     fn test_difference() {
         let mut a = linear::LinearSet::new();
@@ -746,4 +798,34 @@ mod test_set {
         }
         assert i == expected.len();
     }
+
+    #[test]
+    fn test_union() {
+        let mut a = linear::LinearSet::new();
+        let mut b = linear::LinearSet::new();
+
+        assert a.insert(1);
+        assert a.insert(3);
+        assert a.insert(5);
+        assert a.insert(9);
+        assert a.insert(11);
+        assert a.insert(16);
+        assert a.insert(19);
+        assert a.insert(24);
+
+        assert b.insert(-2);
+        assert b.insert(1);
+        assert b.insert(5);
+        assert b.insert(9);
+        assert b.insert(13);
+        assert b.insert(19);
+
+        let mut i = 0;
+        let expected = [-2, 1, 3, 5, 9, 11, 13, 16, 19, 24];
+        for a.union(&b) |x| {
+            assert vec::contains(expected, x);
+            i += 1
+        }
+        assert i == expected.len();
+    }
 }

src/libstd/treemap.rs

@@ -432,22 +432,6 @@ impl <T: Ord> TreeSet<T>: Set<T> {
             }
         }
     }
-}
-
-impl <T: Ord> TreeSet<T> {
-    /// Create an empty TreeSet
-    static pure fn new() -> TreeSet<T> { TreeSet{map: TreeMap::new()} }
-
-    /// Visit all values in reverse order
-    pure fn each_reverse(&self, f: fn(&T) -> bool) {
-        self.map.each_key_reverse(f)
-    }
-
-    /// Get a lazy iterator over the values in the set.
-    /// Requires that it be frozen (immutable).
-    pure fn iter(&self) -> TreeSetIterator/&self<T> {
-        TreeSetIterator{iter: self.map.iter()}
-    }
 
     /// Visit the values (in-order) representing the intersection
     pure fn intersection(&self, other: &TreeSet<T>, f: fn(&T) -> bool) {
@@ -516,6 +500,22 @@ impl <T: Ord> TreeSet<T> {
     }
 }
 
+impl <T: Ord> TreeSet<T> {
+    /// Create an empty TreeSet
+    static pure fn new() -> TreeSet<T> { TreeSet{map: TreeMap::new()} }
+
+    /// Visit all values in reverse order
+    pure fn each_reverse(&self, f: fn(&T) -> bool) {
+        self.map.each_key_reverse(f)
+    }
+
+    /// Get a lazy iterator over the values in the set.
+    /// Requires that it be frozen (immutable).
+    pure fn iter(&self) -> TreeSetIterator/&self<T> {
+        TreeSetIterator{iter: self.map.iter()}
+    }
+}
+
 /// Lazy forward iterator over a set
 pub struct TreeSetIterator<T> {
     priv iter: TreeMapIterator<T, ()>