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Posted to dev@tapestry.apache.org by hl...@apache.org on 2011/10/24 18:15:47 UTC

svn commit: r1188194 - /tapestry/tapestry5/trunk/tapestry-core/src/main/resources/org/apache/tapestry5/underscore_1_1_7.js

Author: hlship
Date: Mon Oct 24 16:15:47 2011
New Revision: 1188194

URL: http://svn.apache.org/viewvc?rev=1188194&view=rev
Log:
TAP5-1716: Zone updates fail due to underscore.js critical bug

Modified:
    tapestry/tapestry5/trunk/tapestry-core/src/main/resources/org/apache/tapestry5/underscore_1_1_7.js

Modified: tapestry/tapestry5/trunk/tapestry-core/src/main/resources/org/apache/tapestry5/underscore_1_1_7.js
URL: http://svn.apache.org/viewvc/tapestry/tapestry5/trunk/tapestry-core/src/main/resources/org/apache/tapestry5/underscore_1_1_7.js?rev=1188194&r1=1188193&r2=1188194&view=diff
==============================================================================
--- tapestry/tapestry5/trunk/tapestry-core/src/main/resources/org/apache/tapestry5/underscore_1_1_7.js (original)
+++ tapestry/tapestry5/trunk/tapestry-core/src/main/resources/org/apache/tapestry5/underscore_1_1_7.js Mon Oct 24 16:15:47 2011
@@ -6,834 +6,855 @@
 //     For all details and documentation:
 //     http://documentcloud.github.com/underscore
 
+// Contains a patch, as reported in:
+// https://issues.apache.org/jira/browse/TAP5-1716
+
 (function() {
 
-  // Baseline setup
-  // --------------
+    // Baseline setup
+    // --------------
+
+    // Establish the root object, `window` in the browser, or `global` on the server.
+    var root = this;
 
-  // Establish the root object, `window` in the browser, or `global` on the server.
-  var root = this;
+    // Save the previous value of the `_` variable.
+    var previousUnderscore = root._;
 
-  // Save the previous value of the `_` variable.
-  var previousUnderscore = root._;
+    // Establish the object that gets returned to break out of a loop iteration.
+    var breaker = {};
+
+    // Save bytes in the minified (but not gzipped) version:
+    var ArrayProto = Array.prototype, ObjProto = Object.prototype, FuncProto = Function.prototype;
+
+    // Create quick reference variables for speed access to core prototypes.
+    var slice = ArrayProto.slice,
+        unshift = ArrayProto.unshift,
+        toString = ObjProto.toString,
+        hasOwnProperty = ObjProto.hasOwnProperty;
+
+    // All **ECMAScript 5** native function implementations that we hope to use
+    // are declared here.
+    var
+        nativeForEach = ArrayProto.forEach,
+        nativeMap = ArrayProto.map,
+        nativeReduce = ArrayProto.reduce,
+        nativeReduceRight = ArrayProto.reduceRight,
+        nativeFilter = ArrayProto.filter,
+        nativeEvery = ArrayProto.every,
+        nativeSome = ArrayProto.some,
+        nativeIndexOf = ArrayProto.indexOf,
+        nativeLastIndexOf = ArrayProto.lastIndexOf,
+        nativeIsArray = Array.isArray,
+        nativeKeys = Object.keys,
+        nativeBind = FuncProto.bind;
+
+    // Create a safe reference to the Underscore object for use below.
+    var _ = function(obj) {
+        return new wrapper(obj);
+    };
 
-  // Establish the object that gets returned to break out of a loop iteration.
-  var breaker = {};
-
-  // Save bytes in the minified (but not gzipped) version:
-  var ArrayProto = Array.prototype, ObjProto = Object.prototype, FuncProto = Function.prototype;
-
-  // Create quick reference variables for speed access to core prototypes.
-  var slice            = ArrayProto.slice,
-      unshift          = ArrayProto.unshift,
-      toString         = ObjProto.toString,
-      hasOwnProperty   = ObjProto.hasOwnProperty;
-
-  // All **ECMAScript 5** native function implementations that we hope to use
-  // are declared here.
-  var
-    nativeForEach      = ArrayProto.forEach,
-    nativeMap          = ArrayProto.map,
-    nativeReduce       = ArrayProto.reduce,
-    nativeReduceRight  = ArrayProto.reduceRight,
-    nativeFilter       = ArrayProto.filter,
-    nativeEvery        = ArrayProto.every,
-    nativeSome         = ArrayProto.some,
-    nativeIndexOf      = ArrayProto.indexOf,
-    nativeLastIndexOf  = ArrayProto.lastIndexOf,
-    nativeIsArray      = Array.isArray,
-    nativeKeys         = Object.keys,
-    nativeBind         = FuncProto.bind;
-
-  // Create a safe reference to the Underscore object for use below.
-  var _ = function(obj) { return new wrapper(obj); };
-
-  // Export the Underscore object for **CommonJS**, with backwards-compatibility
-  // for the old `require()` API. If we're not in CommonJS, add `_` to the
-  // global object.
-  if (typeof module !== 'undefined' && module.exports) {
-    module.exports = _;
-    _._ = _;
-  } else {
-    // Exported as a string, for Closure Compiler "advanced" mode.
-    root['_'] = _;
-  }
-
-  // Current version.
-  _.VERSION = '1.1.7';
-
-  // Collection Functions
-  // --------------------
-
-  // The cornerstone, an `each` implementation, aka `forEach`.
-  // Handles objects with the built-in `forEach`, arrays, and raw objects.
-  // Delegates to **ECMAScript 5**'s native `forEach` if available.
-  var each = _.each = _.forEach = function(obj, iterator, context) {
-    if (obj == null) return;
-    if (nativeForEach && obj.forEach === nativeForEach) {
-      obj.forEach(iterator, context);
-    } else if (obj.length === +obj.length) {
-      for (var i = 0, l = obj.length; i < l; i++) {
-        if (i in obj && iterator.call(context, obj[i], i, obj) === breaker) return;
-      }
+    // Export the Underscore object for **CommonJS**, with backwards-compatibility
+    // for the old `require()` API. If we're not in CommonJS, add `_` to the
+    // global object.
+    if (typeof module !== 'undefined' && module.exports) {
+        module.exports = _;
+        _._ = _;
     } else {
-      for (var key in obj) {
-        if (hasOwnProperty.call(obj, key)) {
-          if (iterator.call(context, obj[key], key, obj) === breaker) return;
-        }
-      }
+        // Exported as a string, for Closure Compiler "advanced" mode.
+        root['_'] = _;
     }
-  };
 
-  // Return the results of applying the iterator to each element.
-  // Delegates to **ECMAScript 5**'s native `map` if available.
-  _.map = function(obj, iterator, context) {
-    var results = [];
-    if (obj == null) return results;
-    if (nativeMap && obj.map === nativeMap) return obj.map(iterator, context);
-    each(obj, function(value, index, list) {
-      results[results.length] = iterator.call(context, value, index, list);
-    });
-    return results;
-  };
+    // Current version.
+    _.VERSION = '1.1.7';
 
-  // **Reduce** builds up a single result from a list of values, aka `inject`,
-  // or `foldl`. Delegates to **ECMAScript 5**'s native `reduce` if available.
-  _.reduce = _.foldl = _.inject = function(obj, iterator, memo, context) {
-    var initial = memo !== void 0;
-    if (obj == null) obj = [];
-    if (nativeReduce && obj.reduce === nativeReduce) {
-      if (context) iterator = _.bind(iterator, context);
-      return initial ? obj.reduce(iterator, memo) : obj.reduce(iterator);
-    }
-    each(obj, function(value, index, list) {
-      if (!initial) {
-        memo = value;
-        initial = true;
-      } else {
-        memo = iterator.call(context, memo, value, index, list);
-      }
-    });
-    if (!initial) throw new TypeError("Reduce of empty array with no initial value");
-    return memo;
-  };
-
-  // The right-associative version of reduce, also known as `foldr`.
-  // Delegates to **ECMAScript 5**'s native `reduceRight` if available.
-  _.reduceRight = _.foldr = function(obj, iterator, memo, context) {
-    if (obj == null) obj = [];
-    if (nativeReduceRight && obj.reduceRight === nativeReduceRight) {
-      if (context) iterator = _.bind(iterator, context);
-      return memo !== void 0 ? obj.reduceRight(iterator, memo) : obj.reduceRight(iterator);
-    }
-    var reversed = (_.isArray(obj) ? obj.slice() : _.toArray(obj)).reverse();
-    return _.reduce(reversed, iterator, memo, context);
-  };
-
-  // Return the first value which passes a truth test. Aliased as `detect`.
-  _.find = _.detect = function(obj, iterator, context) {
-    var result;
-    any(obj, function(value, index, list) {
-      if (iterator.call(context, value, index, list)) {
-        result = value;
+    // Collection Functions
+    // --------------------
+
+    // The cornerstone, an `each` implementation, aka `forEach`.
+    // Handles objects with the built-in `forEach`, arrays, and raw objects.
+    // Delegates to **ECMAScript 5**'s native `forEach` if available.
+    var each = _.each = _.forEach = function(obj, iterator, context) {
+        if (obj == null) return;
+        if (nativeForEach && obj.forEach === nativeForEach) {
+            obj.forEach(iterator, context);
+        } else if (obj.length === +obj.length) {
+            for (var i = 0, l = obj.length; i < l; i++) {
+                if (i in obj && iterator.call(context, obj[i], i, obj) === breaker) return;
+            }
+        } else {
+            for (var key in obj) {
+                if (hasOwnProperty.call(obj, key)) {
+                    if (iterator.call(context, obj[key], key, obj) === breaker) return;
+                }
+            }
+        }
+    };
+
+    // Return the results of applying the iterator to each element.
+    // Delegates to **ECMAScript 5**'s native `map` if available.
+    _.map = function(obj, iterator, context) {
+        var results = [];
+        if (obj == null) return results;
+        if (nativeMap && obj.map === nativeMap) return obj.map(iterator, context);
+        each(obj, function(value, index, list) {
+            results[results.length] = iterator.call(context, value, index, list);
+        });
+        return results;
+    };
+
+    // **Reduce** builds up a single result from a list of values, aka `inject`,
+    // or `foldl`. Delegates to **ECMAScript 5**'s native `reduce` if available.
+    _.reduce = _.foldl = _.inject = function(obj, iterator, memo, context) {
+        var initial = memo !== void 0;
+        if (obj == null) obj = [];
+        if (nativeReduce && obj.reduce === nativeReduce) {
+            if (context) iterator = _.bind(iterator, context);
+            return initial ? obj.reduce(iterator, memo) : obj.reduce(iterator);
+        }
+        each(obj, function(value, index, list) {
+            if (!initial) {
+                memo = value;
+                initial = true;
+            } else {
+                memo = iterator.call(context, memo, value, index, list);
+            }
+        });
+        if (!initial) throw new TypeError("Reduce of empty array with no initial value");
+        return memo;
+    };
+
+    // The right-associative version of reduce, also known as `foldr`.
+    // Delegates to **ECMAScript 5**'s native `reduceRight` if available.
+    _.reduceRight = _.foldr = function(obj, iterator, memo, context) {
+        if (obj == null) obj = [];
+        if (nativeReduceRight && obj.reduceRight === nativeReduceRight) {
+            if (context) iterator = _.bind(iterator, context);
+            return memo !== void 0 ? obj.reduceRight(iterator, memo) : obj.reduceRight(iterator);
+        }
+        var reversed = (_.isArray(obj) ? obj.slice() : _.toArray(obj)).reverse();
+        return _.reduce(reversed, iterator, memo, context);
+    };
+
+    // Return the first value which passes a truth test. Aliased as `detect`.
+    _.find = _.detect = function(obj, iterator, context) {
+        var result;
+        any(obj, function(value, index, list) {
+            if (iterator.call(context, value, index, list)) {
+                result = value;
+                return true;
+            }
+        });
+        return result;
+    };
+
+    // Return all the elements that pass a truth test.
+    // Delegates to **ECMAScript 5**'s native `filter` if available.
+    // Aliased as `select`.
+    _.filter = _.select = function(obj, iterator, context) {
+        var results = [];
+        if (obj == null) return results;
+        if (nativeFilter && obj.filter === nativeFilter) return obj.filter(iterator, context);
+        each(obj, function(value, index, list) {
+            if (iterator.call(context, value, index, list)) results[results.length] = value;
+        });
+        return results;
+    };
+
+    // Return all the elements for which a truth test fails.
+    _.reject = function(obj, iterator, context) {
+        var results = [];
+        if (obj == null) return results;
+        each(obj, function(value, index, list) {
+            if (!iterator.call(context, value, index, list)) results[results.length] = value;
+        });
+        return results;
+    };
+
+    // Determine whether all of the elements match a truth test.
+    // Delegates to **ECMAScript 5**'s native `every` if available.
+    // Aliased as `all`.
+    _.every = _.all = function(obj, iterator, context) {
+        var result = true;
+        if (obj == null) return result;
+        if (nativeEvery && obj.every === nativeEvery) return obj.every(iterator, context);
+        each(obj, function(value, index, list) {
+            if (!(result = result && iterator.call(context, value, index, list))) return breaker;
+        });
+        return result;
+    };
+
+    // Determine if at least one element in the object matches a truth test.
+    // Delegates to **ECMAScript 5**'s native `some` if available.
+    // Aliased as `any`.
+    var any = _.some = _.any = function(obj, iterator, context) {
+        iterator = iterator || _.identity;
+        var result = false;
+        if (obj == null) return result;
+        if (nativeSome && obj.some === nativeSome) return obj.some(iterator, context);
+        each(obj, function(value, index, list) {
+            if (result |= iterator.call(context, value, index, list)) return breaker;
+        });
+        return !!result;
+    };
+
+    // Determine if a given value is included in the array or object using `===`.
+    // Aliased as `contains`.
+    _.include = _.contains = function(obj, target) {
+        var found = false;
+        if (obj == null) return found;
+        if (nativeIndexOf && obj.indexOf === nativeIndexOf) return obj.indexOf(target) != -1;
+        // Patched (TAP5-1716)
+        found = any(obj, function(value) {
+            if (value === target) return true;
+        });
+        return found;
+    };
+
+    // Invoke a method (with arguments) on every item in a collection.
+    _.invoke = function(obj, method) {
+        var args = slice.call(arguments, 2);
+        return _.map(obj, function(value) {
+            return (method.call ? method || value : value[method]).apply(value, args);
+        });
+    };
+
+    // Convenience version of a common use case of `map`: fetching a property.
+    _.pluck = function(obj, key) {
+        return _.map(obj, function(value) {
+            return value[key];
+        });
+    };
+
+    // Return the maximum element or (element-based computation).
+    _.max = function(obj, iterator, context) {
+        if (!iterator && _.isArray(obj)) return Math.max.apply(Math, obj);
+        var result = {computed : -Infinity};
+        each(obj, function(value, index, list) {
+            var computed = iterator ? iterator.call(context, value, index, list) : value;
+            computed >= result.computed && (result = {value : value, computed : computed});
+        });
+        return result.value;
+    };
+
+    // Return the minimum element (or element-based computation).
+    _.min = function(obj, iterator, context) {
+        if (!iterator && _.isArray(obj)) return Math.min.apply(Math, obj);
+        var result = {computed : Infinity};
+        each(obj, function(value, index, list) {
+            var computed = iterator ? iterator.call(context, value, index, list) : value;
+            computed < result.computed && (result = {value : value, computed : computed});
+        });
+        return result.value;
+    };
+
+    // Sort the object's values by a criterion produced by an iterator.
+    _.sortBy = function(obj, iterator, context) {
+        return _.pluck(_.map(obj,
+            function(value, index, list) {
+                return {
+                    value : value,
+                    criteria : iterator.call(context, value, index, list)
+                };
+            }).sort(function(left, right) {
+                var a = left.criteria, b = right.criteria;
+                return a < b ? -1 : a > b ? 1 : 0;
+            }), 'value');
+    };
+
+    // Groups the object's values by a criterion produced by an iterator
+    _.groupBy = function(obj, iterator) {
+        var result = {};
+        each(obj, function(value, index) {
+            var key = iterator(value, index);
+            (result[key] || (result[key] = [])).push(value);
+        });
+        return result;
+    };
+
+    // Use a comparator function to figure out at what index an object should
+    // be inserted so as to maintain order. Uses binary search.
+    _.sortedIndex = function(array, obj, iterator) {
+        iterator || (iterator = _.identity);
+        var low = 0, high = array.length;
+        while (low < high) {
+            var mid = (low + high) >> 1;
+            iterator(array[mid]) < iterator(obj) ? low = mid + 1 : high = mid;
+        }
+        return low;
+    };
+
+    // Safely convert anything iterable into a real, live array.
+    _.toArray = function(iterable) {
+        if (!iterable)                return [];
+        if (iterable.toArray)         return iterable.toArray();
+        if (_.isArray(iterable))      return slice.call(iterable);
+        if (_.isArguments(iterable))  return slice.call(iterable);
+        return _.values(iterable);
+    };
+
+    // Return the number of elements in an object.
+    _.size = function(obj) {
+        return _.toArray(obj).length;
+    };
+
+    // Array Functions
+    // ---------------
+
+    // Get the first element of an array. Passing **n** will return the first N
+    // values in the array. Aliased as `head`. The **guard** check allows it to work
+    // with `_.map`.
+    _.first = _.head = function(array, n, guard) {
+        return (n != null) && !guard ? slice.call(array, 0, n) : array[0];
+    };
+
+    // Returns everything but the first entry of the array. Aliased as `tail`.
+    // Especially useful on the arguments object. Passing an **index** will return
+    // the rest of the values in the array from that index onward. The **guard**
+    // check allows it to work with `_.map`.
+    _.rest = _.tail = function(array, index, guard) {
+        return slice.call(array, (index == null) || guard ? 1 : index);
+    };
+
+    // Get the last element of an array.
+    _.last = function(array) {
+        return array[array.length - 1];
+    };
+
+    // Trim out all falsy values from an array.
+    _.compact = function(array) {
+        return _.filter(array, function(value) {
+            return !!value;
+        });
+    };
+
+    // Return a completely flattened version of an array.
+    _.flatten = function(array) {
+        return _.reduce(array, function(memo, value) {
+            if (_.isArray(value)) return memo.concat(_.flatten(value));
+            memo[memo.length] = value;
+            return memo;
+        }, []);
+    };
+
+    // Return a version of the array that does not contain the specified value(s).
+    _.without = function(array) {
+        return _.difference(array, slice.call(arguments, 1));
+    };
+
+    // Produce a duplicate-free version of the array. If the array has already
+    // been sorted, you have the option of using a faster algorithm.
+    // Aliased as `unique`.
+    _.uniq = _.unique = function(array, isSorted) {
+        return _.reduce(array, function(memo, el, i) {
+            if (0 == i || (isSorted === true ? _.last(memo) != el : !_.include(memo, el))) memo[memo.length] = el;
+            return memo;
+        }, []);
+    };
+
+    // Produce an array that contains the union: each distinct element from all of
+    // the passed-in arrays.
+    _.union = function() {
+        return _.uniq(_.flatten(arguments));
+    };
+
+    // Produce an array that contains every item shared between all the
+    // passed-in arrays. (Aliased as "intersect" for back-compat.)
+    _.intersection = _.intersect = function(array) {
+        var rest = slice.call(arguments, 1);
+        return _.filter(_.uniq(array), function(item) {
+            return _.every(rest, function(other) {
+                return _.indexOf(other, item) >= 0;
+            });
+        });
+    };
+
+    // Take the difference between one array and another.
+    // Only the elements present in just the first array will remain.
+    _.difference = function(array, other) {
+        return _.filter(array, function(value) {
+            return !_.include(other, value);
+        });
+    };
+
+    // Zip together multiple lists into a single array -- elements that share
+    // an index go together.
+    _.zip = function() {
+        var args = slice.call(arguments);
+        var length = _.max(_.pluck(args, 'length'));
+        var results = new Array(length);
+        for (var i = 0; i < length; i++) results[i] = _.pluck(args, "" + i);
+        return results;
+    };
+
+    // If the browser doesn't supply us with indexOf (I'm looking at you, **MSIE**),
+    // we need this function. Return the position of the first occurrence of an
+    // item in an array, or -1 if the item is not included in the array.
+    // Delegates to **ECMAScript 5**'s native `indexOf` if available.
+    // If the array is large and already in sort order, pass `true`
+    // for **isSorted** to use binary search.
+    _.indexOf = function(array, item, isSorted) {
+        if (array == null) return -1;
+        var i, l;
+        if (isSorted) {
+            i = _.sortedIndex(array, item);
+            return array[i] === item ? i : -1;
+        }
+        if (nativeIndexOf && array.indexOf === nativeIndexOf) return array.indexOf(item);
+        for (i = 0,l = array.length; i < l; i++) if (array[i] === item) return i;
+        return -1;
+    };
+
+
+    // Delegates to **ECMAScript 5**'s native `lastIndexOf` if available.
+    _.lastIndexOf = function(array, item) {
+        if (array == null) return -1;
+        if (nativeLastIndexOf && array.lastIndexOf === nativeLastIndexOf) return array.lastIndexOf(item);
+        var i = array.length;
+        while (i--) if (array[i] === item) return i;
+        return -1;
+    };
+
+    // Generate an integer Array containing an arithmetic progression. A port of
+    // the native Python `range()` function. See
+    // [the Python documentation](http://docs.python.org/library/functions.html#range).
+    _.range = function(start, stop, step) {
+        if (arguments.length <= 1) {
+            stop = start || 0;
+            start = 0;
+        }
+        step = arguments[2] || 1;
+
+        var len = Math.max(Math.ceil((stop - start) / step), 0);
+        var idx = 0;
+        var range = new Array(len);
+
+        while (idx < len) {
+            range[idx++] = start;
+            start += step;
+        }
+
+        return range;
+    };
+
+    // Function (ahem) Functions
+    // ------------------
+
+    // Create a function bound to a given object (assigning `this`, and arguments,
+    // optionally). Binding with arguments is also known as `curry`.
+    // Delegates to **ECMAScript 5**'s native `Function.bind` if available.
+    // We check for `func.bind` first, to fail fast when `func` is undefined.
+    _.bind = function(func, obj) {
+        if (func.bind === nativeBind && nativeBind) return nativeBind.apply(func, slice.call(arguments, 1));
+        var args = slice.call(arguments, 2);
+        return function() {
+            return func.apply(obj, args.concat(slice.call(arguments)));
+        };
+    };
+
+    // Bind all of an object's methods to that object. Useful for ensuring that
+    // all callbacks defined on an object belong to it.
+    _.bindAll = function(obj) {
+        var funcs = slice.call(arguments, 1);
+        if (funcs.length == 0) funcs = _.functions(obj);
+        each(funcs, function(f) {
+            obj[f] = _.bind(obj[f], obj);
+        });
+        return obj;
+    };
+
+    // Memoize an expensive function by storing its results.
+    _.memoize = function(func, hasher) {
+        var memo = {};
+        hasher || (hasher = _.identity);
+        return function() {
+            var key = hasher.apply(this, arguments);
+            return hasOwnProperty.call(memo, key) ? memo[key] : (memo[key] = func.apply(this, arguments));
+        };
+    };
+
+    // Delays a function for the given number of milliseconds, and then calls
+    // it with the arguments supplied.
+    _.delay = function(func, wait) {
+        var args = slice.call(arguments, 2);
+        return setTimeout(function() {
+            return func.apply(func, args);
+        }, wait);
+    };
+
+    // Defers a function, scheduling it to run after the current call stack has
+    // cleared.
+    _.defer = function(func) {
+        return _.delay.apply(_, [func, 1].concat(slice.call(arguments, 1)));
+    };
+
+    // Internal function used to implement `_.throttle` and `_.debounce`.
+    var limit = function(func, wait, debounce) {
+        var timeout;
+        return function() {
+            var context = this, args = arguments;
+            var throttler = function() {
+                timeout = null;
+                func.apply(context, args);
+            };
+            if (debounce) clearTimeout(timeout);
+            if (debounce || !timeout) timeout = setTimeout(throttler, wait);
+        };
+    };
+
+    // Returns a function, that, when invoked, will only be triggered at most once
+    // during a given window of time.
+    _.throttle = function(func, wait) {
+        return limit(func, wait, false);
+    };
+
+    // Returns a function, that, as long as it continues to be invoked, will not
+    // be triggered. The function will be called after it stops being called for
+    // N milliseconds.
+    _.debounce = function(func, wait) {
+        return limit(func, wait, true);
+    };
+
+    // Returns a function that will be executed at most one time, no matter how
+    // often you call it. Useful for lazy initialization.
+    _.once = function(func) {
+        var ran = false, memo;
+        return function() {
+            if (ran) return memo;
+            ran = true;
+            return memo = func.apply(this, arguments);
+        };
+    };
+
+    // Returns the first function passed as an argument to the second,
+    // allowing you to adjust arguments, run code before and after, and
+    // conditionally execute the original function.
+    _.wrap = function(func, wrapper) {
+        return function() {
+            var args = [func].concat(slice.call(arguments));
+            return wrapper.apply(this, args);
+        };
+    };
+
+    // Returns a function that is the composition of a list of functions, each
+    // consuming the return value of the function that follows.
+    _.compose = function() {
+        var funcs = slice.call(arguments);
+        return function() {
+            var args = slice.call(arguments);
+            for (var i = funcs.length - 1; i >= 0; i--) {
+                args = [funcs[i].apply(this, args)];
+            }
+            return args[0];
+        };
+    };
+
+    // Returns a function that will only be executed after being called N times.
+    _.after = function(times, func) {
+        return function() {
+            if (--times < 1) {
+                return func.apply(this, arguments);
+            }
+        };
+    };
+
+
+    // Object Functions
+    // ----------------
+
+    // Retrieve the names of an object's properties.
+    // Delegates to **ECMAScript 5**'s native `Object.keys`
+    _.keys = nativeKeys || function(obj) {
+        if (obj !== Object(obj)) throw new TypeError('Invalid object');
+        var keys = [];
+        for (var key in obj) if (hasOwnProperty.call(obj, key)) keys[keys.length] = key;
+        return keys;
+    };
+
+    // Retrieve the values of an object's properties.
+    _.values = function(obj) {
+        return _.map(obj, _.identity);
+    };
+
+    // Return a sorted list of the function names available on the object.
+    // Aliased as `methods`
+    _.functions = _.methods = function(obj) {
+        var names = [];
+        for (var key in obj) {
+            if (_.isFunction(obj[key])) names.push(key);
+        }
+        return names.sort();
+    };
+
+    // Extend a given object with all the properties in passed-in object(s).
+    _.extend = function(obj) {
+        each(slice.call(arguments, 1), function(source) {
+            for (var prop in source) {
+                if (source[prop] !== void 0) obj[prop] = source[prop];
+            }
+        });
+        return obj;
+    };
+
+    // Fill in a given object with default properties.
+    _.defaults = function(obj) {
+        each(slice.call(arguments, 1), function(source) {
+            for (var prop in source) {
+                if (obj[prop] == null) obj[prop] = source[prop];
+            }
+        });
+        return obj;
+    };
+
+    // Create a (shallow-cloned) duplicate of an object.
+    _.clone = function(obj) {
+        return _.isArray(obj) ? obj.slice() : _.extend({}, obj);
+    };
+
+    // Invokes interceptor with the obj, and then returns obj.
+    // The primary purpose of this method is to "tap into" a method chain, in
+    // order to perform operations on intermediate results within the chain.
+    _.tap = function(obj, interceptor) {
+        interceptor(obj);
+        return obj;
+    };
+
+    // Perform a deep comparison to check if two objects are equal.
+    _.isEqual = function(a, b) {
+        // Check object identity.
+        if (a === b) return true;
+        // Different types?
+        var atype = typeof(a), btype = typeof(b);
+        if (atype != btype) return false;
+        // Basic equality test (watch out for coercions).
+        if (a == b) return true;
+        // One is falsy and the other truthy.
+        if ((!a && b) || (a && !b)) return false;
+        // Unwrap any wrapped objects.
+        if (a._chain) a = a._wrapped;
+        if (b._chain) b = b._wrapped;
+        // One of them implements an isEqual()?
+        if (a.isEqual) return a.isEqual(b);
+        if (b.isEqual) return b.isEqual(a);
+        // Check dates' integer values.
+        if (_.isDate(a) && _.isDate(b)) return a.getTime() === b.getTime();
+        // Both are NaN?
+        if (_.isNaN(a) && _.isNaN(b)) return false;
+        // Compare regular expressions.
+        if (_.isRegExp(a) && _.isRegExp(b))
+            return a.source === b.source &&
+                a.global === b.global &&
+                a.ignoreCase === b.ignoreCase &&
+                a.multiline === b.multiline;
+        // If a is not an object by this point, we can't handle it.
+        if (atype !== 'object') return false;
+        // Check for different array lengths before comparing contents.
+        if (a.length && (a.length !== b.length)) return false;
+        // Nothing else worked, deep compare the contents.
+        var aKeys = _.keys(a), bKeys = _.keys(b);
+        // Different object sizes?
+        if (aKeys.length != bKeys.length) return false;
+        // Recursive comparison of contents.
+        for (var key in a) if (!(key in b) || !_.isEqual(a[key], b[key])) return false;
         return true;
-      }
-    });
-    return result;
-  };
+    };
 
-  // Return all the elements that pass a truth test.
-  // Delegates to **ECMAScript 5**'s native `filter` if available.
-  // Aliased as `select`.
-  _.filter = _.select = function(obj, iterator, context) {
-    var results = [];
-    if (obj == null) return results;
-    if (nativeFilter && obj.filter === nativeFilter) return obj.filter(iterator, context);
-    each(obj, function(value, index, list) {
-      if (iterator.call(context, value, index, list)) results[results.length] = value;
-    });
-    return results;
-  };
+    // Is a given array or object empty?
+    _.isEmpty = function(obj) {
+        if (_.isArray(obj) || _.isString(obj)) return obj.length === 0;
+        for (var key in obj) if (hasOwnProperty.call(obj, key)) return false;
+        return true;
+    };
 
-  // Return all the elements for which a truth test fails.
-  _.reject = function(obj, iterator, context) {
-    var results = [];
-    if (obj == null) return results;
-    each(obj, function(value, index, list) {
-      if (!iterator.call(context, value, index, list)) results[results.length] = value;
-    });
-    return results;
-  };
+    // Is a given value a DOM element?
+    _.isElement = function(obj) {
+        return !!(obj && obj.nodeType == 1);
+    };
 
-  // Determine whether all of the elements match a truth test.
-  // Delegates to **ECMAScript 5**'s native `every` if available.
-  // Aliased as `all`.
-  _.every = _.all = function(obj, iterator, context) {
-    var result = true;
-    if (obj == null) return result;
-    if (nativeEvery && obj.every === nativeEvery) return obj.every(iterator, context);
-    each(obj, function(value, index, list) {
-      if (!(result = result && iterator.call(context, value, index, list))) return breaker;
-    });
-    return result;
-  };
+    // Is a given value an array?
+    // Delegates to ECMA5's native Array.isArray
+    _.isArray = nativeIsArray || function(obj) {
+        return toString.call(obj) === '[object Array]';
+    };
 
-  // Determine if at least one element in the object matches a truth test.
-  // Delegates to **ECMAScript 5**'s native `some` if available.
-  // Aliased as `any`.
-  var any = _.some = _.any = function(obj, iterator, context) {
-    iterator = iterator || _.identity;
-    var result = false;
-    if (obj == null) return result;
-    if (nativeSome && obj.some === nativeSome) return obj.some(iterator, context);
-    each(obj, function(value, index, list) {
-      if (result |= iterator.call(context, value, index, list)) return breaker;
-    });
-    return !!result;
-  };
+    // Is a given variable an object?
+    _.isObject = function(obj) {
+        return obj === Object(obj);
+    };
 
-  // Determine if a given value is included in the array or object using `===`.
-  // Aliased as `contains`.
-  _.include = _.contains = function(obj, target) {
-    var found = false;
-    if (obj == null) return found;
-    if (nativeIndexOf && obj.indexOf === nativeIndexOf) return obj.indexOf(target) != -1;
-    any(obj, function(value) {
-      if (found = value === target) return true;
-    });
-    return found;
-  };
+    // Is a given variable an arguments object?
+    _.isArguments = function(obj) {
+        return !!(obj && hasOwnProperty.call(obj, 'callee'));
+    };
 
-  // Invoke a method (with arguments) on every item in a collection.
-  _.invoke = function(obj, method) {
-    var args = slice.call(arguments, 2);
-    return _.map(obj, function(value) {
-      return (method.call ? method || value : value[method]).apply(value, args);
-    });
-  };
+    // Is a given value a function?
+    _.isFunction = function(obj) {
+        return !!(obj && obj.constructor && obj.call && obj.apply);
+    };
 
-  // Convenience version of a common use case of `map`: fetching a property.
-  _.pluck = function(obj, key) {
-    return _.map(obj, function(value){ return value[key]; });
-  };
-
-  // Return the maximum element or (element-based computation).
-  _.max = function(obj, iterator, context) {
-    if (!iterator && _.isArray(obj)) return Math.max.apply(Math, obj);
-    var result = {computed : -Infinity};
-    each(obj, function(value, index, list) {
-      var computed = iterator ? iterator.call(context, value, index, list) : value;
-      computed >= result.computed && (result = {value : value, computed : computed});
-    });
-    return result.value;
-  };
+    // Is a given value a string?
+    _.isString = function(obj) {
+        return !!(obj === '' || (obj && obj.charCodeAt && obj.substr));
+    };
 
-  // Return the minimum element (or element-based computation).
-  _.min = function(obj, iterator, context) {
-    if (!iterator && _.isArray(obj)) return Math.min.apply(Math, obj);
-    var result = {computed : Infinity};
-    each(obj, function(value, index, list) {
-      var computed = iterator ? iterator.call(context, value, index, list) : value;
-      computed < result.computed && (result = {value : value, computed : computed});
-    });
-    return result.value;
-  };
+    // Is a given value a number?
+    _.isNumber = function(obj) {
+        return !!(obj === 0 || (obj && obj.toExponential && obj.toFixed));
+    };
 
-  // Sort the object's values by a criterion produced by an iterator.
-  _.sortBy = function(obj, iterator, context) {
-    return _.pluck(_.map(obj, function(value, index, list) {
-      return {
-        value : value,
-        criteria : iterator.call(context, value, index, list)
-      };
-    }).sort(function(left, right) {
-      var a = left.criteria, b = right.criteria;
-      return a < b ? -1 : a > b ? 1 : 0;
-    }), 'value');
-  };
-
-  // Groups the object's values by a criterion produced by an iterator
-  _.groupBy = function(obj, iterator) {
-    var result = {};
-    each(obj, function(value, index) {
-      var key = iterator(value, index);
-      (result[key] || (result[key] = [])).push(value);
-    });
-    return result;
-  };
+    // Is the given value `NaN`? `NaN` happens to be the only value in JavaScript
+    // that does not equal itself.
+    _.isNaN = function(obj) {
+        return obj !== obj;
+    };
 
-  // Use a comparator function to figure out at what index an object should
-  // be inserted so as to maintain order. Uses binary search.
-  _.sortedIndex = function(array, obj, iterator) {
-    iterator || (iterator = _.identity);
-    var low = 0, high = array.length;
-    while (low < high) {
-      var mid = (low + high) >> 1;
-      iterator(array[mid]) < iterator(obj) ? low = mid + 1 : high = mid;
-    }
-    return low;
-  };
+    // Is a given value a boolean?
+    _.isBoolean = function(obj) {
+        return obj === true || obj === false;
+    };
 
-  // Safely convert anything iterable into a real, live array.
-  _.toArray = function(iterable) {
-    if (!iterable)                return [];
-    if (iterable.toArray)         return iterable.toArray();
-    if (_.isArray(iterable))      return slice.call(iterable);
-    if (_.isArguments(iterable))  return slice.call(iterable);
-    return _.values(iterable);
-  };
-
-  // Return the number of elements in an object.
-  _.size = function(obj) {
-    return _.toArray(obj).length;
-  };
-
-  // Array Functions
-  // ---------------
-
-  // Get the first element of an array. Passing **n** will return the first N
-  // values in the array. Aliased as `head`. The **guard** check allows it to work
-  // with `_.map`.
-  _.first = _.head = function(array, n, guard) {
-    return (n != null) && !guard ? slice.call(array, 0, n) : array[0];
-  };
-
-  // Returns everything but the first entry of the array. Aliased as `tail`.
-  // Especially useful on the arguments object. Passing an **index** will return
-  // the rest of the values in the array from that index onward. The **guard**
-  // check allows it to work with `_.map`.
-  _.rest = _.tail = function(array, index, guard) {
-    return slice.call(array, (index == null) || guard ? 1 : index);
-  };
-
-  // Get the last element of an array.
-  _.last = function(array) {
-    return array[array.length - 1];
-  };
-
-  // Trim out all falsy values from an array.
-  _.compact = function(array) {
-    return _.filter(array, function(value){ return !!value; });
-  };
-
-  // Return a completely flattened version of an array.
-  _.flatten = function(array) {
-    return _.reduce(array, function(memo, value) {
-      if (_.isArray(value)) return memo.concat(_.flatten(value));
-      memo[memo.length] = value;
-      return memo;
-    }, []);
-  };
-
-  // Return a version of the array that does not contain the specified value(s).
-  _.without = function(array) {
-    return _.difference(array, slice.call(arguments, 1));
-  };
-
-  // Produce a duplicate-free version of the array. If the array has already
-  // been sorted, you have the option of using a faster algorithm.
-  // Aliased as `unique`.
-  _.uniq = _.unique = function(array, isSorted) {
-    return _.reduce(array, function(memo, el, i) {
-      if (0 == i || (isSorted === true ? _.last(memo) != el : !_.include(memo, el))) memo[memo.length] = el;
-      return memo;
-    }, []);
-  };
-
-  // Produce an array that contains the union: each distinct element from all of
-  // the passed-in arrays.
-  _.union = function() {
-    return _.uniq(_.flatten(arguments));
-  };
-
-  // Produce an array that contains every item shared between all the
-  // passed-in arrays. (Aliased as "intersect" for back-compat.)
-  _.intersection = _.intersect = function(array) {
-    var rest = slice.call(arguments, 1);
-    return _.filter(_.uniq(array), function(item) {
-      return _.every(rest, function(other) {
-        return _.indexOf(other, item) >= 0;
-      });
-    });
-  };
+    // Is a given value a date?
+    _.isDate = function(obj) {
+        return !!(obj && obj.getTimezoneOffset && obj.setUTCFullYear);
+    };
 
-  // Take the difference between one array and another.
-  // Only the elements present in just the first array will remain.
-  _.difference = function(array, other) {
-    return _.filter(array, function(value){ return !_.include(other, value); });
-  };
-
-  // Zip together multiple lists into a single array -- elements that share
-  // an index go together.
-  _.zip = function() {
-    var args = slice.call(arguments);
-    var length = _.max(_.pluck(args, 'length'));
-    var results = new Array(length);
-    for (var i = 0; i < length; i++) results[i] = _.pluck(args, "" + i);
-    return results;
-  };
-
-  // If the browser doesn't supply us with indexOf (I'm looking at you, **MSIE**),
-  // we need this function. Return the position of the first occurrence of an
-  // item in an array, or -1 if the item is not included in the array.
-  // Delegates to **ECMAScript 5**'s native `indexOf` if available.
-  // If the array is large and already in sort order, pass `true`
-  // for **isSorted** to use binary search.
-  _.indexOf = function(array, item, isSorted) {
-    if (array == null) return -1;
-    var i, l;
-    if (isSorted) {
-      i = _.sortedIndex(array, item);
-      return array[i] === item ? i : -1;
-    }
-    if (nativeIndexOf && array.indexOf === nativeIndexOf) return array.indexOf(item);
-    for (i = 0, l = array.length; i < l; i++) if (array[i] === item) return i;
-    return -1;
-  };
-
-
-  // Delegates to **ECMAScript 5**'s native `lastIndexOf` if available.
-  _.lastIndexOf = function(array, item) {
-    if (array == null) return -1;
-    if (nativeLastIndexOf && array.lastIndexOf === nativeLastIndexOf) return array.lastIndexOf(item);
-    var i = array.length;
-    while (i--) if (array[i] === item) return i;
-    return -1;
-  };
-
-  // Generate an integer Array containing an arithmetic progression. A port of
-  // the native Python `range()` function. See
-  // [the Python documentation](http://docs.python.org/library/functions.html#range).
-  _.range = function(start, stop, step) {
-    if (arguments.length <= 1) {
-      stop = start || 0;
-      start = 0;
-    }
-    step = arguments[2] || 1;
+    // Is the given value a regular expression?
+    _.isRegExp = function(obj) {
+        return !!(obj && obj.test && obj.exec && (obj.ignoreCase || obj.ignoreCase === false));
+    };
 
-    var len = Math.max(Math.ceil((stop - start) / step), 0);
-    var idx = 0;
-    var range = new Array(len);
-
-    while(idx < len) {
-      range[idx++] = start;
-      start += step;
-    }
+    // Is a given value equal to null?
+    _.isNull = function(obj) {
+        return obj === null;
+    };
 
-    return range;
-  };
+    // Is a given variable undefined?
+    _.isUndefined = function(obj) {
+        return obj === void 0;
+    };
 
-  // Function (ahem) Functions
-  // ------------------
+    // Utility Functions
+    // -----------------
 
-  // Create a function bound to a given object (assigning `this`, and arguments,
-  // optionally). Binding with arguments is also known as `curry`.
-  // Delegates to **ECMAScript 5**'s native `Function.bind` if available.
-  // We check for `func.bind` first, to fail fast when `func` is undefined.
-  _.bind = function(func, obj) {
-    if (func.bind === nativeBind && nativeBind) return nativeBind.apply(func, slice.call(arguments, 1));
-    var args = slice.call(arguments, 2);
-    return function() {
-      return func.apply(obj, args.concat(slice.call(arguments)));
-    };
-  };
-
-  // Bind all of an object's methods to that object. Useful for ensuring that
-  // all callbacks defined on an object belong to it.
-  _.bindAll = function(obj) {
-    var funcs = slice.call(arguments, 1);
-    if (funcs.length == 0) funcs = _.functions(obj);
-    each(funcs, function(f) { obj[f] = _.bind(obj[f], obj); });
-    return obj;
-  };
-
-  // Memoize an expensive function by storing its results.
-  _.memoize = function(func, hasher) {
-    var memo = {};
-    hasher || (hasher = _.identity);
-    return function() {
-      var key = hasher.apply(this, arguments);
-      return hasOwnProperty.call(memo, key) ? memo[key] : (memo[key] = func.apply(this, arguments));
-    };
-  };
-
-  // Delays a function for the given number of milliseconds, and then calls
-  // it with the arguments supplied.
-  _.delay = function(func, wait) {
-    var args = slice.call(arguments, 2);
-    return setTimeout(function(){ return func.apply(func, args); }, wait);
-  };
-
-  // Defers a function, scheduling it to run after the current call stack has
-  // cleared.
-  _.defer = function(func) {
-    return _.delay.apply(_, [func, 1].concat(slice.call(arguments, 1)));
-  };
-
-  // Internal function used to implement `_.throttle` and `_.debounce`.
-  var limit = function(func, wait, debounce) {
-    var timeout;
-    return function() {
-      var context = this, args = arguments;
-      var throttler = function() {
-        timeout = null;
-        func.apply(context, args);
-      };
-      if (debounce) clearTimeout(timeout);
-      if (debounce || !timeout) timeout = setTimeout(throttler, wait);
-    };
-  };
-
-  // Returns a function, that, when invoked, will only be triggered at most once
-  // during a given window of time.
-  _.throttle = function(func, wait) {
-    return limit(func, wait, false);
-  };
-
-  // Returns a function, that, as long as it continues to be invoked, will not
-  // be triggered. The function will be called after it stops being called for
-  // N milliseconds.
-  _.debounce = function(func, wait) {
-    return limit(func, wait, true);
-  };
-
-  // Returns a function that will be executed at most one time, no matter how
-  // often you call it. Useful for lazy initialization.
-  _.once = function(func) {
-    var ran = false, memo;
-    return function() {
-      if (ran) return memo;
-      ran = true;
-      return memo = func.apply(this, arguments);
-    };
-  };
-
-  // Returns the first function passed as an argument to the second,
-  // allowing you to adjust arguments, run code before and after, and
-  // conditionally execute the original function.
-  _.wrap = function(func, wrapper) {
-    return function() {
-      var args = [func].concat(slice.call(arguments));
-      return wrapper.apply(this, args);
-    };
-  };
-
-  // Returns a function that is the composition of a list of functions, each
-  // consuming the return value of the function that follows.
-  _.compose = function() {
-    var funcs = slice.call(arguments);
-    return function() {
-      var args = slice.call(arguments);
-      for (var i = funcs.length - 1; i >= 0; i--) {
-        args = [funcs[i].apply(this, args)];
-      }
-      return args[0];
-    };
-  };
-
-  // Returns a function that will only be executed after being called N times.
-  _.after = function(times, func) {
-    return function() {
-      if (--times < 1) { return func.apply(this, arguments); }
-    };
-  };
-
-
-  // Object Functions
-  // ----------------
-
-  // Retrieve the names of an object's properties.
-  // Delegates to **ECMAScript 5**'s native `Object.keys`
-  _.keys = nativeKeys || function(obj) {
-    if (obj !== Object(obj)) throw new TypeError('Invalid object');
-    var keys = [];
-    for (var key in obj) if (hasOwnProperty.call(obj, key)) keys[keys.length] = key;
-    return keys;
-  };
-
-  // Retrieve the values of an object's properties.
-  _.values = function(obj) {
-    return _.map(obj, _.identity);
-  };
-
-  // Return a sorted list of the function names available on the object.
-  // Aliased as `methods`
-  _.functions = _.methods = function(obj) {
-    var names = [];
-    for (var key in obj) {
-      if (_.isFunction(obj[key])) names.push(key);
-    }
-    return names.sort();
-  };
+    // Run Underscore.js in *noConflict* mode, returning the `_` variable to its
+    // previous owner. Returns a reference to the Underscore object.
+    _.noConflict = function() {
+        root._ = previousUnderscore;
+        return this;
+    };
 
-  // Extend a given object with all the properties in passed-in object(s).
-  _.extend = function(obj) {
-    each(slice.call(arguments, 1), function(source) {
-      for (var prop in source) {
-        if (source[prop] !== void 0) obj[prop] = source[prop];
-      }
-    });
-    return obj;
-  };
+    // Keep the identity function around for default iterators.
+    _.identity = function(value) {
+        return value;
+    };
 
-  // Fill in a given object with default properties.
-  _.defaults = function(obj) {
-    each(slice.call(arguments, 1), function(source) {
-      for (var prop in source) {
-        if (obj[prop] == null) obj[prop] = source[prop];
-      }
-    });
-    return obj;
-  };
+    // Run a function **n** times.
+    _.times = function (n, iterator, context) {
+        for (var i = 0; i < n; i++) iterator.call(context, i);
+    };
 
-  // Create a (shallow-cloned) duplicate of an object.
-  _.clone = function(obj) {
-    return _.isArray(obj) ? obj.slice() : _.extend({}, obj);
-  };
-
-  // Invokes interceptor with the obj, and then returns obj.
-  // The primary purpose of this method is to "tap into" a method chain, in
-  // order to perform operations on intermediate results within the chain.
-  _.tap = function(obj, interceptor) {
-    interceptor(obj);
-    return obj;
-  };
-
-  // Perform a deep comparison to check if two objects are equal.
-  _.isEqual = function(a, b) {
-    // Check object identity.
-    if (a === b) return true;
-    // Different types?
-    var atype = typeof(a), btype = typeof(b);
-    if (atype != btype) return false;
-    // Basic equality test (watch out for coercions).
-    if (a == b) return true;
-    // One is falsy and the other truthy.
-    if ((!a && b) || (a && !b)) return false;
-    // Unwrap any wrapped objects.
-    if (a._chain) a = a._wrapped;
-    if (b._chain) b = b._wrapped;
-    // One of them implements an isEqual()?
-    if (a.isEqual) return a.isEqual(b);
-    if (b.isEqual) return b.isEqual(a);
-    // Check dates' integer values.
-    if (_.isDate(a) && _.isDate(b)) return a.getTime() === b.getTime();
-    // Both are NaN?
-    if (_.isNaN(a) && _.isNaN(b)) return false;
-    // Compare regular expressions.
-    if (_.isRegExp(a) && _.isRegExp(b))
-      return a.source     === b.source &&
-             a.global     === b.global &&
-             a.ignoreCase === b.ignoreCase &&
-             a.multiline  === b.multiline;
-    // If a is not an object by this point, we can't handle it.
-    if (atype !== 'object') return false;
-    // Check for different array lengths before comparing contents.
-    if (a.length && (a.length !== b.length)) return false;
-    // Nothing else worked, deep compare the contents.
-    var aKeys = _.keys(a), bKeys = _.keys(b);
-    // Different object sizes?
-    if (aKeys.length != bKeys.length) return false;
-    // Recursive comparison of contents.
-    for (var key in a) if (!(key in b) || !_.isEqual(a[key], b[key])) return false;
-    return true;
-  };
-
-  // Is a given array or object empty?
-  _.isEmpty = function(obj) {
-    if (_.isArray(obj) || _.isString(obj)) return obj.length === 0;
-    for (var key in obj) if (hasOwnProperty.call(obj, key)) return false;
-    return true;
-  };
-
-  // Is a given value a DOM element?
-  _.isElement = function(obj) {
-    return !!(obj && obj.nodeType == 1);
-  };
-
-  // Is a given value an array?
-  // Delegates to ECMA5's native Array.isArray
-  _.isArray = nativeIsArray || function(obj) {
-    return toString.call(obj) === '[object Array]';
-  };
-
-  // Is a given variable an object?
-  _.isObject = function(obj) {
-    return obj === Object(obj);
-  };
-
-  // Is a given variable an arguments object?
-  _.isArguments = function(obj) {
-    return !!(obj && hasOwnProperty.call(obj, 'callee'));
-  };
-
-  // Is a given value a function?
-  _.isFunction = function(obj) {
-    return !!(obj && obj.constructor && obj.call && obj.apply);
-  };
-
-  // Is a given value a string?
-  _.isString = function(obj) {
-    return !!(obj === '' || (obj && obj.charCodeAt && obj.substr));
-  };
-
-  // Is a given value a number?
-  _.isNumber = function(obj) {
-    return !!(obj === 0 || (obj && obj.toExponential && obj.toFixed));
-  };
-
-  // Is the given value `NaN`? `NaN` happens to be the only value in JavaScript
-  // that does not equal itself.
-  _.isNaN = function(obj) {
-    return obj !== obj;
-  };
-
-  // Is a given value a boolean?
-  _.isBoolean = function(obj) {
-    return obj === true || obj === false;
-  };
-
-  // Is a given value a date?
-  _.isDate = function(obj) {
-    return !!(obj && obj.getTimezoneOffset && obj.setUTCFullYear);
-  };
-
-  // Is the given value a regular expression?
-  _.isRegExp = function(obj) {
-    return !!(obj && obj.test && obj.exec && (obj.ignoreCase || obj.ignoreCase === false));
-  };
-
-  // Is a given value equal to null?
-  _.isNull = function(obj) {
-    return obj === null;
-  };
-
-  // Is a given variable undefined?
-  _.isUndefined = function(obj) {
-    return obj === void 0;
-  };
-
-  // Utility Functions
-  // -----------------
-
-  // Run Underscore.js in *noConflict* mode, returning the `_` variable to its
-  // previous owner. Returns a reference to the Underscore object.
-  _.noConflict = function() {
-    root._ = previousUnderscore;
-    return this;
-  };
-
-  // Keep the identity function around for default iterators.
-  _.identity = function(value) {
-    return value;
-  };
-
-  // Run a function **n** times.
-  _.times = function (n, iterator, context) {
-    for (var i = 0; i < n; i++) iterator.call(context, i);
-  };
-
-  // Add your own custom functions to the Underscore object, ensuring that
-  // they're correctly added to the OOP wrapper as well.
-  _.mixin = function(obj) {
-    each(_.functions(obj), function(name){
-      addToWrapper(name, _[name] = obj[name]);
-    });
-  };
+    // Add your own custom functions to the Underscore object, ensuring that
+    // they're correctly added to the OOP wrapper as well.
+    _.mixin = function(obj) {
+        each(_.functions(obj), function(name) {
+            addToWrapper(name, _[name] = obj[name]);
+        });
+    };
+
+    // Generate a unique integer id (unique within the entire client session).
+    // Useful for temporary DOM ids.
+    var idCounter = 0;
+    _.uniqueId = function(prefix) {
+        var id = idCounter++;
+        return prefix ? prefix + id : id;
+    };
+
+    // By default, Underscore uses ERB-style template delimiters, change the
+    // following template settings to use alternative delimiters.
+    _.templateSettings = {
+        evaluate    : /<%([\s\S]+?)%>/g,
+        interpolate : /<%=([\s\S]+?)%>/g
+    };
+
+    // JavaScript micro-templating, similar to John Resig's implementation.
+    // Underscore templating handles arbitrary delimiters, preserves whitespace,
+    // and correctly escapes quotes within interpolated code.
+    _.template = function(str, data) {
+        var c = _.templateSettings;
+        var tmpl = 'var __p=[],print=function(){__p.push.apply(__p,arguments);};' +
+            'with(obj||{}){__p.push(\'' +
+            str.replace(/\\/g, '\\\\')
+                .replace(/'/g, "\\'")
+                .replace(c.interpolate, function(match, code) {
+                    return "'," + code.replace(/\\'/g, "'") + ",'";
+                })
+                .replace(c.evaluate || null, function(match, code) {
+                    return "');" + code.replace(/\\'/g, "'")
+                        .replace(/[\r\n\t]/g, ' ') + "__p.push('";
+                })
+                .replace(/\r/g, '\\r')
+                .replace(/\n/g, '\\n')
+                .replace(/\t/g, '\\t')
+            + "');}return __p.join('');";
+        var func = new Function('obj', tmpl);
+        return data ? func(data) : func;
+    };
+
+    // The OOP Wrapper
+    // ---------------
 
-  // Generate a unique integer id (unique within the entire client session).
-  // Useful for temporary DOM ids.
-  var idCounter = 0;
-  _.uniqueId = function(prefix) {
-    var id = idCounter++;
-    return prefix ? prefix + id : id;
-  };
-
-  // By default, Underscore uses ERB-style template delimiters, change the
-  // following template settings to use alternative delimiters.
-  _.templateSettings = {
-    evaluate    : /<%([\s\S]+?)%>/g,
-    interpolate : /<%=([\s\S]+?)%>/g
-  };
-
-  // JavaScript micro-templating, similar to John Resig's implementation.
-  // Underscore templating handles arbitrary delimiters, preserves whitespace,
-  // and correctly escapes quotes within interpolated code.
-  _.template = function(str, data) {
-    var c  = _.templateSettings;
-    var tmpl = 'var __p=[],print=function(){__p.push.apply(__p,arguments);};' +
-      'with(obj||{}){__p.push(\'' +
-      str.replace(/\\/g, '\\\\')
-         .replace(/'/g, "\\'")
-         .replace(c.interpolate, function(match, code) {
-           return "'," + code.replace(/\\'/g, "'") + ",'";
-         })
-         .replace(c.evaluate || null, function(match, code) {
-           return "');" + code.replace(/\\'/g, "'")
-                              .replace(/[\r\n\t]/g, ' ') + "__p.push('";
-         })
-         .replace(/\r/g, '\\r')
-         .replace(/\n/g, '\\n')
-         .replace(/\t/g, '\\t')
-         + "');}return __p.join('');";
-    var func = new Function('obj', tmpl);
-    return data ? func(data) : func;
-  };
-
-  // The OOP Wrapper
-  // ---------------
-
-  // If Underscore is called as a function, it returns a wrapped object that
-  // can be used OO-style. This wrapper holds altered versions of all the
-  // underscore functions. Wrapped objects may be chained.
-  var wrapper = function(obj) { this._wrapped = obj; };
-
-  // Expose `wrapper.prototype` as `_.prototype`
-  _.prototype = wrapper.prototype;
-
-  // Helper function to continue chaining intermediate results.
-  var result = function(obj, chain) {
-    return chain ? _(obj).chain() : obj;
-  };
-
-  // A method to easily add functions to the OOP wrapper.
-  var addToWrapper = function(name, func) {
-    wrapper.prototype[name] = function() {
-      var args = slice.call(arguments);
-      unshift.call(args, this._wrapped);
-      return result(func.apply(_, args), this._chain);
-    };
-  };
-
-  // Add all of the Underscore functions to the wrapper object.
-  _.mixin(_);
-
-  // Add all mutator Array functions to the wrapper.
-  each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) {
-    var method = ArrayProto[name];
-    wrapper.prototype[name] = function() {
-      method.apply(this._wrapped, arguments);
-      return result(this._wrapped, this._chain);
-    };
-  });
-
-  // Add all accessor Array functions to the wrapper.
-  each(['concat', 'join', 'slice'], function(name) {
-    var method = ArrayProto[name];
-    wrapper.prototype[name] = function() {
-      return result(method.apply(this._wrapped, arguments), this._chain);
-    };
-  });
-
-  // Start chaining a wrapped Underscore object.
-  wrapper.prototype.chain = function() {
-    this._chain = true;
-    return this;
-  };
-
-  // Extracts the result from a wrapped and chained object.
-  wrapper.prototype.value = function() {
-    return this._wrapped;
-  };
+    // If Underscore is called as a function, it returns a wrapped object that
+    // can be used OO-style. This wrapper holds altered versions of all the
+    // underscore functions. Wrapped objects may be chained.
+    var wrapper = function(obj) {
+        this._wrapped = obj;
+    };
+
+    // Expose `wrapper.prototype` as `_.prototype`
+    _.prototype = wrapper.prototype;
+
+    // Helper function to continue chaining intermediate results.
+    var result = function(obj, chain) {
+        return chain ? _(obj).chain() : obj;
+    };
+
+    // A method to easily add functions to the OOP wrapper.
+    var addToWrapper = function(name, func) {
+        wrapper.prototype[name] = function() {
+            var args = slice.call(arguments);
+            unshift.call(args, this._wrapped);
+            return result(func.apply(_, args), this._chain);
+        };
+    };
+
+    // Add all of the Underscore functions to the wrapper object.
+    _.mixin(_);
+
+    // Add all mutator Array functions to the wrapper.
+    each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) {
+        var method = ArrayProto[name];
+        wrapper.prototype[name] = function() {
+            method.apply(this._wrapped, arguments);
+            return result(this._wrapped, this._chain);
+        };
+    });
+
+    // Add all accessor Array functions to the wrapper.
+    each(['concat', 'join', 'slice'], function(name) {
+        var method = ArrayProto[name];
+        wrapper.prototype[name] = function() {
+            return result(method.apply(this._wrapped, arguments), this._chain);
+        };
+    });
+
+    // Start chaining a wrapped Underscore object.
+    wrapper.prototype.chain = function() {
+        this._chain = true;
+        return this;
+    };
+
+    // Extracts the result from a wrapped and chained object.
+    wrapper.prototype.value = function() {
+        return this._wrapped;
+    };
 
 })();