core: Make range follow the for loop protocol

src/libcore/int-template.rs

@@ -36,9 +36,12 @@ pure fn is_nonpositive(x: T) -> bool { x <= 0 as T }
 pure fn is_nonnegative(x: T) -> bool { x >= 0 as T }
 
 #[doc = "Iterate over the range [`lo`..`hi`)"]
-fn range(lo: T, hi: T, it: fn(T)) {
+fn range(lo: T, hi: T, it: fn(T) -> bool) {
     let mut i = lo;
-    while i < hi { it(i); i += 1 as T; }
+    while i < hi {
+        if !it(i) { break }
+        i += 1 as T;
+    }
 }
 
 #[doc = "Computes the bitwise complement"]

src/libcore/priv.rs

@@ -127,12 +127,12 @@ fn test_from_global_chan2() unsafe {
 
         // Spawn a bunch of tasks that all want to compete to
         // create the global channel
-        uint::range(0u, 10u) {|i|
+        for uint::range(0u, 10u) {|i|
             task::spawn() {||
                 let ch = chan_from_global_ptr(
                     globchanp, task::builder) {|po|
 
-                    uint::range(0u, 10u) {|_j|
+                    for uint::range(0u, 10u) {|_j|
                         let ch = comm::recv(po);
                         comm::send(ch, {i});
                     }
@@ -147,7 +147,7 @@ fn test_from_global_chan2() unsafe {
         }
         // There should be only one winner
         let mut winners = 0u;
-        uint::range(0u, 10u) {|_i|
+        for uint::range(0u, 10u) {|_i|
             let res = comm::recv(resultpo);
             if res { winners += 1u };
         }

src/libcore/rand.rs

@@ -202,7 +202,7 @@ impl extensions for rng {
     fn weighted_vec<T:copy>(v: [weighted<T>]) -> [T] {
         let mut r = [];
         for v.each {|item|
-            uint::range(0u, item.weight) {|_i|
+            for uint::range(0u, item.weight) {|_i|
                 r += [item.item];
             }
         }

src/libcore/uint-template.rs

@@ -35,9 +35,12 @@ pure fn is_nonpositive(x: T) -> bool { x <= 0 as T }
 pure fn is_nonnegative(x: T) -> bool { x >= 0 as T }
 
 #[doc = "Iterate over the range [`lo`..`hi`)"]
-fn range(lo: T, hi: T, it: fn(T)) {
+fn range(lo: T, hi: T, it: fn(T) -> bool) {
     let mut i = lo;
-    while i < hi { it(i); i += 1 as T; }
+    while i < hi {
+        if !it(i) { break }
+        i += 1 as T;
+    }
 }
 
 #[doc = "Computes the bitwise complement"]

src/libcore/vec.rs

@@ -892,7 +892,7 @@ Both vectors must have the same length
 #[inline]
 fn iter2<U, T>(v1: [const U], v2: [const T], f: fn(U, T)) {
     assert len(v1) == len(v2);
-    uint::range(0u, len(v1)) {|i|
+    for uint::range(0u, len(v1)) {|i|
         f(v1[i], v2[i])
     }
 }