Convenience methods for spawning and joining tasks.

src/lib/task.rs

@@ -73,8 +73,17 @@ tag task_notification {
     exit(task, task_result);
 }
 
-fn join(t: task) -> task_result {
-    join_id(cast(t))
+fn join(task_port : (task_id, comm::port<task_notification>))
+    -> task_result {
+    let (id, port) = task_port;
+    while true {
+        alt comm::recv::<task_notification>(port) {
+          exit(_id, res) {
+            if _id == id { ret res }
+          }
+        }
+    }
+    fail
 }
 
 fn join_id(t : task_id) -> task_result {
@@ -104,6 +113,12 @@ fn spawn_notify(thunk : -fn() -> (), notify : _chan<task_notification>)
     spawn_inner(thunk, some(notify))
 }
 
+fn spawn_joinable(thunk : -fn()) -> (task_id, comm::port<task_notification>) {
+    let p = comm::port::<task_notification>();
+    let id = spawn_notify(thunk, comm::chan::<task_notification>(p));
+    ret (id, p);
+}
+
 // FIXME: make this a fn~ once those are supported.
 fn spawn_inner(thunk : -fn() -> (),
                notify : option<_chan<task_notification>>)

src/test/stdtest/task.rs

@@ -72,3 +72,11 @@ fn test_join_chan_fail() {
       _ { fail "invalid task status received" }
     }
 }
+
+#[test]
+fn test_join_convenient() {
+    fn winner() { }
+    let f = winner;
+    let handle = task::spawn_joinable(f);
+    assert(task::tr_success == task::join(handle));
+}