From 8cac2d5bd75c606fa987a97a97213e48974ed7f0 Mon Sep 17 00:00:00 2001
From: Luke Sutton <luke.sutton@gmail.com>
Date: Thu, 19 Nov 2009 11:07:14 +1030
Subject: [PATCH 1/2] Add init(), tail() and reverse() Array functions. Alias
 first() to head();

---
 test/arrays.js | 15 +++++++++++++++
 underscore.js  | 24 ++++++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/test/arrays.js b/test/arrays.js
index d069d9d62..a9dcb4e90 100644
--- a/test/arrays.js
+++ b/test/arrays.js
@@ -58,4 +58,19 @@ $(document).ready(function() {
     equals(_.lastIndexOf(numbers, 0), 8, 'lastIndexOf the other element');
   });
   
+  test("arrays: tail", function() {
+    var numbers = [1, 2, 3, 4];
+    equals(_.tail(numbers).join(", "), "2, 3, 4");
+  });
+  
+  test("arrays: init", function() {
+    var numbers = [1, 2, 3, 4];
+    equals(_.init(numbers).join(", "), "1, 2, 3");
+  });
+  
+  test("arrays: reverse", function() {
+    var numbers = [1, 2, 4, 6];
+    equals(_.reverse(numbers).join(", "), "6, 4, 2, 1");
+  });
+  
 });
diff --git a/underscore.js b/underscore.js
index ac1b8659d..ad6dbecac 100644
--- a/underscore.js
+++ b/underscore.js
@@ -305,6 +305,29 @@
     while (i--) if (array[i] === item) return i;
     return -1;
   };
+  
+  // Returns everything but the first entry of the array. Conceptually the 
+  // same as calling shift(), but doesn't mutate the array passed in.
+  _.tail = function(array) {
+    var tail = _.clone(array);
+    tail.shift();
+    return tail;
+  };
+  
+  // Returns everything but the last entry of the array. Conceptually the 
+  // same as calling pop(), but doesn't mutate the array passed in.
+  _.init = function(array) {
+    var init = _.clone(array);
+    init.pop();
+    return init;
+  };
+
+  // Returns a new array, with the entries or the passed-in array in reverse
+  // order.
+  _.reverse = function(array) {
+    var reverse = _.clone(array);
+    return reverse.reverse();
+  };
 
   /* ----------------------- Function Functions: -----------------------------*/
 
@@ -501,6 +524,7 @@
 
   /*------------------------------- Aliases ----------------------------------*/
 
+  _.head     = _.first;
   _.forEach  = _.each;
   _.foldl    = _.inject       = _.reduce;
   _.foldr    = _.reduceRight;

From 4ed79d5f778e8e8eb5fa0232545ac719cf4c9d42 Mon Sep 17 00:00:00 2001
From: Luke Sutton <luke.sutton@gmail.com>
Date: Thu, 19 Nov 2009 11:35:21 +1030
Subject: [PATCH 2/2] Correct the test for functions() to account for the new
 functions and aliases.

---
 test/utility.js | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/test/utility.js b/test/utility.js
index ed6ee120b..0acc6a16d 100644
--- a/test/utility.js
+++ b/test/utility.js
@@ -31,13 +31,13 @@ $(document).ready(function() {
   });
 
   test("utility: functions", function() {
-    var expected = ["all", "any", "bind", "bindAll", "breakLoop", "clone", "compact", "compose",
-    "defer", "delay", "detect", "each", "every", "extend", "filter", "first",
-    "flatten", "foldl", "foldr", "forEach", "functions", "identity", "include",
-    "indexOf", "inject", "intersect", "invoke", "isArray", "isElement", "isEmpty", "isEqual",
+    var expected = ["all", "any", "bind", "bindAll", "breakLoop", "clone", "compact", 
+    "compose","defer", "delay", "detect", "each", "every", "extend", "filter", "first",
+    "flatten", "foldl", "foldr", "forEach", "functions", "head", "identity", "include",
+    "indexOf", "init", "inject", "intersect", "invoke", "isArray", "isElement", "isEmpty", "isEqual",
     "isFunction", "isNumber", "isString", "isUndefined", "keys", "last", "lastIndexOf", "map", "max",
-    "methods", "min", "pluck", "reduce", "reduceRight", "reject", "select",
-    "size", "some", "sortBy", "sortedIndex", "template", "toArray", "uniq",
+    "methods", "min", "pluck", "reduce", "reduceRight", "reject", "reverse", "select",
+    "size", "some", "sortBy", "sortedIndex", "tail", "template", "toArray", "uniq",
     "uniqueId", "values", "without", "wrap", "zip"];
     ok(_(expected).isEqual(_.methods()), 'provides a sorted list of functions');
   });