vec.rs: add new feature ( each2_mut function )

src/libcore/vec.rs

@@ -1681,8 +1681,8 @@ pub fn eachi_reverse<'r,T>(v: &'r [T],
  */
 #[inline]
 pub fn _each2<U, T>(v1: &[U], v2: &[T], f: &fn(u: &U, t: &T) -> bool) -> bool {
-    assert!(len(v1) == len(v2));
-    for uint::range(0u, len(v1)) |i| {
+    assert!(v1.len() == v2.len());
+    for uint::range(0u, v1.len()) |i| {
         if !f(&v1[i], &v2[i]) {
             return false;
         }
@@ -1699,6 +1699,35 @@ pub fn each2<U, T>(v1: &[U], v2: &[T], f: &fn(u: &U, t: &T) -> bool) -> bool {
     _each2(v1, v2, f)
 }
 
+/**
+ *
+ * Iterates over two vector with mutable.
+ *
+ * # Failure
+ *
+ * Both vectors must have the same length
+ */
+#[inline]
+pub fn _each2_mut<U, T>(v1: &mut [U], v2: &mut [T], f: &fn(u: &mut U, t: &mut T) -> bool) -> bool {
+    assert!(v1.len() == v2.len());
+    for uint::range(0u, v1.len()) |i| {
+        if !f(&mut v1[i], &mut v2[i]) {
+            return false;
+        }
+    }
+    return true;
+}
+
+#[cfg(stage0)]
+pub fn each2_mut<U, T>(v1: &mut [U], v2: &mut [T], f: &fn(u: &mut U, t: &mut T) -> bool) {
+    _each2_mut(v1, v2, f);
+}
+
+#[cfg(not(stage0))]
+pub fn each2_mut<U, T>(v1: &mut [U], v2: &mut [T], f: &fn(u: &mut U, t: &mut T) -> bool) -> bool {
+    _each2_mut(v1, v2, f)
+}
+
 /**
  * Iterate over all permutations of vector `v`.
  *

src/test/run-pass/vec-each2_mut.rs

@@ -0,0 +1,38 @@
+// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// -*- rust -*-
+fn main(){
+    let mut t1 = ~[];
+    t1.push('a');
+
+    let mut t2 = ~[];
+    t2.push('b');
+
+    for vec::each2_mut(t1, t2) | i1, i2 | {
+        assert!(*i1 == 'a');
+        assert!(*i2 == 'b');
+    }
+
+    for vec::each2(t1, t2) | i1, i2 | {
+        io::println(fmt!("after t1: %?, t2: %?", i1, i2));
+    }
+
+    for vec::each2_mut(t1, t2) | i1, i2 | {
+        *i1 = 'b';
+        *i2 = 'a';
+        assert!(*i1 == 'b');
+        assert!(*i2 == 'a');
+    }
+
+    for vec::each2(t1, t2) | i1, i2 | {
+        io::println(fmt!("before t1: %?, t2: %?", i1, i2));
+    }
+}