---

yaml
---
r: 8102
b: refs/heads/snap-stage3
c: 91da710
h: refs/heads/master
v: v3

Author: marijnh

[refs]

@@ -1,6 +1,6 @@
 ---
 refs/heads/master: 2898dcc5d97da9427ac367542382b6239d9c0bbf
 refs/heads/snap-stage1: e33de59e47c5076a89eadeb38f4934f58a3618a6
-refs/heads/snap-stage3: e0fa5cd2edbbb611ff3759a31357a70ca9582245
+refs/heads/snap-stage3: 91da710d86a58f4596b6ea22ccf35dd896445ccf
 refs/heads/try: 2898dcc5d97da9427ac367542382b6239d9c0bbf
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105

branches/snap-stage3/src/test/run-pass/monad.rs

@@ -0,0 +1,31 @@
+iface monad<A> {
+    fn bind<B>(fn(A) -> self<B>) -> self<B>;
+}
+
+impl <A> of monad<A> for [A] {
+    fn bind<B>(f: fn(A) -> [B]) -> [B] {
+        let r = [];
+        for elt in self { r += f(elt); }
+        r
+    }
+}
+
+impl <A> of monad<A> for option<A> {
+    fn bind<B>(f: fn(A) -> option<B>) -> option<B> {
+        alt self {
+          some(a) { f(a) }
+          none { none }
+        }
+    }
+}
+
+fn transform(x: option<int>) -> option<str> {
+    x.bind {|n| some(n + 1)}.bind {|n| some(int::str(n))}
+}
+
+fn main() {
+    assert transform(some(10)) == some("11");
+    assert transform(none) == none;
+    assert ["hi"].bind {|x| [x, x + "!"]}.bind {|x| [x, x + "?"]} ==
+        ["hi", "hi?", "hi!", "hi!?"];
+}