From be3a71a1aa36173ce2cd521f811d8010029aa46f Mon Sep 17 00:00:00 2001
From: Ben Blum <bblum@andrew.cmu.edu>
Date: Tue, 24 Jul 2012 15:46:40 -0400
Subject: [PATCH] Add option::unwrap_expect

---
 src/libcore/option.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/libcore/option.rs b/src/libcore/option.rs
index 6cfb18dc644..270ba90c704 100644
--- a/src/libcore/option.rs
+++ b/src/libcore/option.rs
@@ -120,6 +120,12 @@ pure fn unwrap<T>(-opt: option<T>) -> T {
     }
 }
 
+pure fn unwrap_expect<T>(-opt: option<T>, reason: ~str) -> T {
+    //! As unwrap, but with a specified failure message.
+    if opt.is_none() { fail reason; }
+    unwrap(opt)
+}
+
 impl extensions<T> for option<T> {
     /**
      * Update an optional value by optionally running its content through a