---

yaml
---
r: 2805
b: refs/heads/master
c: 22953f5
h: refs/heads/master
i:
  2803: 1b1276a
v: v3

Author: paulstansifer

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: e2bb98001e5946c35952f3e1cd0b8cfbe3915cc1
+refs/heads/master: 22953f52faa3afb24c7024c0373a4895d9c5859b

trunk/src/lib/vec.rs

@@ -220,12 +220,24 @@ fn grow_init_fn_set[T](&array[T] v, uint index, fn()->T init_fn, &T val) {
     v.(index) = val;
 }
 
-fn map[T, U](&option::operator[T,U] f, &array[T] v) -> vec[U] {
-    let vec[U] u = alloc[U](len[T](v));
+
+fn map[T, U](&fn(&T) -> U f, &array[T] v) -> vec[U] {
+    let vec[U] res = alloc[U](len[T](v));
     for (T ve in v) {
-        u += [f(ve)];
+        res += [f(ve)];
     }
-    ret u;
+    ret res;
+}
+
+fn filter_map[T, U](&fn(&T) -> option::t[U] f, &array[T] v) -> vec[U] {
+    let vec[U] res = []; //TODO does this work these days?
+    for(T ve in v) {
+        alt(f(ve)) {
+            case (some[U](?elt)) { res += [elt]; }
+            case (none[U]) {}
+        }
+    }
+    ret res;
 }
 
 fn map2[T,U,V](&operator2[T,U,V] f, &array[T] v0, &array[U] v1) -> vec[V] {

trunk/src/test/run-pass/lib-vec.rs

@@ -56,11 +56,35 @@ fn test_map2() {
   }
 }
 
+fn test_filter_map() {
+  fn halve(&int i) -> std::option::t[int] { 
+    if(i % 2 == 0) { 
+      ret std::option::some[int](i / 2);
+    } else {
+      ret std::option::none[int];
+    }
+  }
+  fn halve_for_sure(&int i) -> int { ret i/2; }
+  
+  let vec[int] all_even = [0, 2, 8, 6];
+  let vec[int] all_odd1 = [1, 7, 3];
+  let vec[int] all_odd2 = [];
+  let vec[int] mix = [9, 2, 6, 7, 1, 0, 0, 3];
+  let vec[int] mix_dest = [1, 3, 0, 0];
+  
+  assert(std::vec::filter_map(halve, all_even) ==
+         std::vec::map(halve_for_sure, all_even));
+  assert(std::vec::filter_map(halve, all_odd1) == std::vec::empty[int]());
+  assert(std::vec::filter_map(halve, all_odd2) == std::vec::empty[int]());
+  assert(std::vec::filter_map(halve, mix) == mix_dest);
+}
+
 fn main() {
   test_init_elt();
   test_init_fn();
   test_slice();
   test_map();
   test_map2();
+  test_filter_map();
 }