---

yaml
---
r: 13743
b: refs/heads/master
c: e56ba15
h: refs/heads/master
i:
  13741: b074ee5
  13739: e35ee99
  13735: 2101da1
  13727: dc60629
v: v3

Author: bblum

[refs]

@@ -1,5 +1,5 @@
 ---
-refs/heads/master: 9f7e62ea209811fd1ca864498761e733f1c99298
+refs/heads/master: e56ba156e223e24025a743247610283cca49b30a
 refs/heads/snap-stage1: e33de59e47c5076a89eadeb38f4934f58a3618a6
 refs/heads/snap-stage3: 4a81779abd786ff22d71434c6d9a5917ea4cdfff
 refs/heads/try: 2898dcc5d97da9427ac367542382b6239d9c0bbf

trunk/src/libcore/iter-trait.rs

@@ -16,6 +16,9 @@ impl extensions<A> of iter::base_iter<A> for IMPL_T<A> {
     }
     fn contains(x: A) -> bool { iter::contains(self, x) }
     fn count(x: A) -> uint { iter::count(self, x) }
+    fn position(f: fn(A) -> bool) -> option<uint> {
+        iter::position(self, f)
+    }
 }
 
 impl extensions<A:copy> for IMPL_T<A> {

trunk/src/libcore/iter.rs

@@ -85,6 +85,20 @@ fn count<A,IA:base_iter<A>>(self: IA, x: A) -> uint {
     }
 }
 
+fn position<A,IA:base_iter<A>>(self: IA, f: fn(A) -> bool)
+        -> option<uint> {
+    let mut i = 0;
+    for self.each {|a|
+        if f(a) { ret some(i); }
+        i += 1;
+    }
+    ret none;
+}
+
+// note: 'rposition' would only make sense to provide with a bidirectional
+// iter interface, such as would provide "reach" in addition to "each". as is,
+// it would have to be implemented with foldr, which is too inefficient.
+
 fn repeat(times: uint, blk: fn()) {
     let mut i = 0u;
     while i < times {