Collection KVC fixes, nextObject correctness

- Moved common CPArray/CPSet collection KVC operators to _CPCollectionKVCOperators.
- Implemented KVC operator dispatch using Objective-J.
- Fixed infinite loop with empty  collection in @min, @max and @sum operators.
- Correctly return valueForUndefinedKey when necessary.
- valueForUndefinedKey reason uses raw description for consistency, class' overridden description may not helpful at all.
- Don't create a forwarder for @ operators with property paths.
- Fixed CPSet -valueForKeyPath to correctly deal with nil/undefined/empty values.
- Added tests for collection  KVC operators.
- enumerator -nextObject should always compare against nil for clarity, correctness, and consistency.

AppKit/CPFlashView.j

@@ -104,10 +104,10 @@ var IEFlashCLSID = "clsid:D27CDB6E-AE6D-11cf-96B8-444553540000";
 - (void)setFlashVars:(CPDictionary)aDictionary
 {
     var varString = @"",
-        enumerator = [aDictionary keyEnumerator];
+        enumerator = [aDictionary keyEnumerator],
+        key;
 
-    var key;
-    while (key = [enumerator nextObject])
+    while ((key = [enumerator nextObject]) !== nil)
         varString = [varString stringByAppendingFormat:@"&%@=%@", key, [aDictionary objectForKey:key]];
 
     if (!_params)
@@ -146,7 +146,7 @@ var IEFlashCLSID = "clsid:D27CDB6E-AE6D-11cf-96B8-444553540000";
         var enumerator = [_params keyEnumerator],
             key;
 
-        while (_DOMObjectElement && (key = [enumerator nextObject]))
+        while (_DOMObjectElement && (key = [enumerator nextObject]) !== nil)
         {
             var param = document.createElement(@"param");
             param.name = key;
@@ -178,7 +178,7 @@ var IEFlashCLSID = "clsid:D27CDB6E-AE6D-11cf-96B8-444553540000";
         paramEnumerator = [_params keyEnumerator],
         key;
 
-    while (key = [paramEnumerator nextObject])
+    while ((key = [paramEnumerator nextObject]) !== nil)
         paramString = [paramString stringByAppendingFormat:@"<param name='%@' value='%@' />", key, [_params objectForKey:key]];
 
     _DOMObjectElement = document.createElement(@"object");

AppKit/CPMenu/_CPMenuManager.j

@@ -473,7 +473,7 @@ var STICKY_TIME_INTERVAL            = 500,
         var iter = [selectorNames objectEnumerator],
             obj;
 
-        while (obj = [iter nextObject])
+        while ((obj = [iter nextObject]) !== nil)
         {
             var aSelector = CPSelectorFromString(obj);
 
@@ -504,7 +504,7 @@ var STICKY_TIME_INTERVAL            = 500,
     var iter = [[menu itemArray] objectEnumerator],
         obj;
 
-    while (obj = [iter nextObject])
+    while ((obj = [iter nextObject]) !== nil)
     {
         if ([obj isHidden] || ![obj isEnabled])
             continue;

AppKit/CPTableView.j

@@ -2689,7 +2689,7 @@ Your delegate can implement this method to avoid subclassing the tableview to ad
         oldMainSortDescriptor = [[self sortDescriptors] objectAtIndex: 0];
 
     // Remove every main descriptor equivalents (normally only one)
-    while ((descriptor = [e nextObject]) != nil)
+    while ((descriptor = [e nextObject]) !== nil)
     {
         if ([[descriptor key] isEqual: [newMainSortDescriptor key]])
             [outdatedDescriptors addObject:descriptor];

AppKit/CPTheme.j

@@ -255,7 +255,7 @@ var CPThemesByName          = { },
         attributeNames = [attributes keyEnumerator],
         objectThemeClass = [anObject themeClass];
 
-    while (attributeName = [attributeNames nextObject])
+    while ((attributeName = [attributeNames nextObject]) !== nil)
         [self _recordAttribute:[attributes objectForKey:attributeName] forClass:objectThemeClass];
 }
 

AppKit/CPView.j

@@ -534,7 +534,7 @@ var CPViewFlags                     = { },
     var addedSubview = nil,
         addedSubviewEnumerator = [addedSubviews objectEnumerator];
 
-    while (addedSubview = [addedSubviewEnumerator nextObject])
+    while ((addedSubview = [addedSubviewEnumerator nextObject]) !== nil)
         [self addSubview:addedSubview];
 
     // If the order is fine, no need to reorder.

AppKit/Cib/CPCib.j

@@ -137,7 +137,7 @@ var CPCibObjectDataKey  = @"CPCibObjectDataKey";
         var key = nil,
             keyEnumerator = [replacementClasses keyEnumerator];
 
-        while (key = [keyEnumerator nextObject])
+        while ((key = [keyEnumerator nextObject]) !== nil)
             [unarchiver setClass:[replacementClasses objectForKey:key] forClassName:key];
     }
 

AppKit/Cib/_CPCibObjectData.j

@@ -106,7 +106,7 @@
     var object = nil,
         objectEnumerator = [_visibleWindows objectEnumerator];
 
-    while (object = [objectEnumerator nextObject])
+    while ((object = [objectEnumerator nextObject]) !== nil)
         [_replacementObjects[[object UID]] makeKeyAndOrderFront:self];
 }
 

AppKit/Platform/DOM/CPPlatformWindow+DOM.j

@@ -1625,7 +1625,7 @@ function CPWindowObjectList()
         platformWindow = nil,
         windowObjects = [];
 
-    while (platformWindow = [platformWindowEnumerator nextObject])
+    while ((platformWindow = [platformWindowEnumerator nextObject]) !== nil)
     {
         var levels = platformWindow._windowLevels,
             layers = platformWindow._windowLayers,

CommonJS/lib/cappuccino/cib-analysis-tools.j

@@ -49,7 +49,7 @@ function findCibClassDependencies(cibPath) {
         var key = nil,
             keyEnumerator = [replacementClasses keyEnumerator];
 
-        while (key = [keyEnumerator nextObject])
+        while ((key = [keyEnumerator nextObject]) !== nil)
             [unarchiver setClass:[replacementClasses objectForKey:key] forClassName:key];
     }
 

Foundation/CPArray+KVO.j

@@ -22,6 +22,7 @@
 
 @import "CPArray.j"
 @import "CPNull.j"
+@import "_CPCollectionKVCOperators.j"
 
 
 @implementation CPObject (CPArrayKVO)
@@ -240,6 +241,7 @@
 {
     if (_objectsAtIndexes)
         return _objectsAtIndexes(_proxyObject, _objectsAtIndexesSEL, theIndexes);
+
     if (_objectAtIndex)
     {
         var index = CPNotFound,
@@ -413,9 +415,9 @@
 @end
 
 
-//KVC on CPArray objects act on each item of the array, rather than on the array itself
+// KVC on CPArray objects act on each item of the array, rather than on the array itself
 
-@implementation CPArray (KeyValueCoding)
+@implementation CPArray (CPKeyValueCoding)
 
 - (id)valueForKey:(CPString)aKey
 {
@@ -424,10 +426,10 @@
         if (aKey.indexOf(".") !== -1)
             [CPException raise:CPInvalidArgumentException reason:"called valueForKey: on an array with a complex key ("+aKey+"). use valueForKeyPath:"];
 
-        if (aKey == "@count")
+        if (aKey === "@count")
             return length;
 
-        return nil;
+        return [self valueForUndefinedKey:aKey];
     }
     else
     {
@@ -451,6 +453,9 @@
 
 - (id)valueForKeyPath:(CPString)aKeyPath
 {
+    if (!aKeyPath)
+        [self valueForUndefinedKey:@"<empty path>"];
+
     if (aKeyPath.charAt(0) === "@")
     {
         var dotIndex = aKeyPath.indexOf("."),
@@ -465,10 +470,7 @@
         else
             operator = aKeyPath.substring(1);
 
-        if (kvoOperators[operator])
-            return kvoOperators[operator](self, _cmd, parameter);
-
-        return nil;
+        return [_CPCollectionKVCOperator performOperation:operator withCollection:self propertyPath:parameter];
     }
     else
     {
@@ -495,7 +497,7 @@
     var enumerator = [self objectEnumerator],
         object;
 
-    while (object = [enumerator nextObject])
+    while ((object = [enumerator nextObject]) !== nil)
         [object setValue:aValue forKey:aKey];
 }
 
@@ -504,86 +506,12 @@
     var enumerator = [self objectEnumerator],
         object;
 
-    while (object = [enumerator nextObject])
+    while ((object = [enumerator nextObject]) !== nil)
         [object setValue:aValue forKeyPath:aKeyPath];
 }
 
 @end
 
-var kvoOperators = [];
-
-// HACK: prevent these from becoming globals. workaround for obj-j "function foo(){}" behavior
-var avgOperator,
-    maxOperator,
-    minOperator,
-    countOperator,
-    sumOperator;
-
-kvoOperators["avg"] = function avgOperator(self, _cmd, param)
-{
-    var objects = [self valueForKeyPath:param],
-        length = [objects count],
-        index = length,
-        average = 0.0;
-
-    if (!length)
-        return 0;
-
-    while (index--)
-        average += [objects[index] doubleValue];
-
-    return average / length;
-}
-
-kvoOperators["max"] = function maxOperator(self, _cmd, param)
-{
-    var objects = [self valueForKeyPath:param],
-        index = [objects count] - 1,
-        max = [objects lastObject];
-
-    while (index--)
-    {
-        var item = objects[index];
-        if ([max compare:item] < 0)
-            max = item;
-    }
-
-    return max;
-}
-
-kvoOperators["min"] = function minOperator(self, _cmd, param)
-{
-    var objects = [self valueForKeyPath:param],
-        index = [objects count] - 1,
-        min = [objects lastObject];
-
-    while (index--)
-    {
-        var item = objects[index];
-        if ([min compare:item] > 0)
-            min = item;
-    }
-
-    return min;
-}
-
-kvoOperators["count"] = function countOperator(self, _cmd, param)
-{
-    return [self count];
-}
-
-kvoOperators["sum"] = function sumOperator(self, _cmd, param)
-{
-    var objects = [self valueForKeyPath:param],
-        index = [objects count],
-        sum = 0.0;
-
-    while (index--)
-        sum += [objects[index] doubleValue];
-
-    return sum;
-}
-
 @implementation CPArray (KeyValueObserving)
 
 - (void)addObserver:(id)anObserver toObjectsAtIndexes:(CPIndexSet)indexes forKeyPath:(CPString)aKeyPath options:(unsigned)options context:(id)context
@@ -610,20 +538,4 @@ kvoOperators["sum"] = function sumOperator(self, _cmd, param)
     }
 }
 
-- (void)addObserver:(id)observer forKeyPath:(CPString)aKeyPath options:(unsigned)options context:(id)context
-{
-    if ([isa instanceMethodForSelector:_cmd] === [CPArray instanceMethodForSelector:_cmd])
-        [CPException raise:CPInvalidArgumentException reason:"Unsupported method on CPArray"];
-    else
-        [super addObserver:observer forKeyPath:aKeyPath options:options context:context];
-}
-
-- (void)removeObserver:(id)observer forKeyPath:(CPString)aKeyPath
-{
-    if ([isa instanceMethodForSelector:_cmd] === [CPArray instanceMethodForSelector:_cmd])
-        [CPException raise:CPInvalidArgumentException reason:"Unsupported method on CPArray"];
-    else
-        [super removeObserver:observer forKeyPath:aKeyPath];
-}
-
 @end

Foundation/CPCharacterSet.j

@@ -241,7 +241,7 @@ var CPCharacterSetInvertedKey = @"CPCharacterSetInvertedKey";
     var enu = [_ranges objectEnumerator],
         range;
 
-    while (range = [enu nextObject])
+    while ((range = [enu nextObject]) !== nil)
     {
         if (CPLocationInRange(c, range))
             return !_inverted;

Foundation/CPDictionary.j

@@ -50,7 +50,7 @@
 {
     var key = [_keyEnumerator nextObject];
 
-    if (!key)
+    if (key === nil)
         return nil;
 
     return [_dictionary objectForKey:key];

Foundation/CPKeyValueCoding.j

@@ -157,7 +157,7 @@ var CPObjectAccessorsForClassKey            = @"$CPObjectAccessorsForClassKey",
 - (id)valueForUndefinedKey:(CPString)aKey
 {
     [[CPException exceptionWithName:CPUndefinedKeyException
-                            reason:[self description] + " is not key value coding-compliant for the key " + aKey
+                            reason:[self _objectDescription] + " is not key value coding-compliant for the key " + aKey
                           userInfo:[CPDictionary dictionaryWithObjects:[self, aKey] forKeys:[CPTargetObjectUserInfoKey, CPUnknownUserInfoKey]]] raise];
 }
 
@@ -235,7 +235,7 @@ var CPObjectAccessorsForClassKey            = @"$CPObjectAccessorsForClassKey",
         key,
         keyEnumerator = [keyedValues keyEnumerator];
 
-    while (key = [keyEnumerator nextObject])
+    while ((key = [keyEnumerator nextObject]) !== nil)
     {
         value = [keyedValues objectForKey: key];
 
@@ -250,10 +250,15 @@ var CPObjectAccessorsForClassKey            = @"$CPObjectAccessorsForClassKey",
 - (void)setValue:(id)aValue forUndefinedKey:(CPString)aKey
 {
     [[CPException exceptionWithName:CPUndefinedKeyException
-                            reason:[self description] + " is not key value coding-compliant for the key " + aKey
+                            reason:[self _objectDescription] + " is not key value coding-compliant for the key " + aKey
                           userInfo:[CPDictionary dictionaryWithObjects:[self, aKey] forKeys:[CPTargetObjectUserInfoKey, CPUnknownUserInfoKey]]] raise];
 }
 
+- (CPString)_objectDescription
+{
+    return "<" + [self className] + " 0x" + [CPString stringWithHash:[self UID]] + ">";
+}
+
 @end
 
 @implementation CPDictionary (CPKeyValueCoding)

Foundation/CPKeyValueObserving.j

@@ -664,7 +664,7 @@ var kvoNewAndOld        = CPKeyValueObservingOptionNew | CPKeyValueObservingOpti
 
     var forwarder = nil;
 
-    if (aPath.indexOf('.') != CPNotFound)
+    if (aPath.indexOf('.') !== CPNotFound && aPath.charAt(0) !== '@')
         forwarder = [[_CPKVOForwardingObserver alloc] initWithKeyPath:aPath object:_targetObject observer:anObserver options:options context:aContext];
     else
         [self _replaceModifiersForKey:aPath];
@@ -1092,7 +1092,7 @@ var kvoNewAndOld        = CPKeyValueObservingOptionNew | CPKeyValueObservingOpti
 
     var dotIndex = aKeyPath.indexOf('.');
 
-    if (dotIndex == CPNotFound)
+    if (dotIndex === CPNotFound)
         [CPException raise:CPInvalidArgumentException reason:"Created _CPKVOForwardingObserver without compound key path: "+aKeyPath];
 
     _firstPart = aKeyPath.substring(0, dotIndex);

Foundation/CPKeyedArchiver.j

@@ -398,7 +398,7 @@ var _CPKeyedArchiverStringClass                         = Nil,
         keys = [aDictionary keyEnumerator],
         references = [CPDictionary dictionary];
 
-    while (key = [keys nextObject])
+    while ((key = [keys nextObject]) !== nil)
         [references setObject:_CPKeyedArchiverEncodeObject(self, [aDictionary objectForKey:key], NO) forKey:key];
 
     [_plistObject setObject:references forKey:aKey];

Foundation/CPNotificationCenter.j

@@ -103,7 +103,7 @@ var CPNotificationDefaultCenter = nil;
     var name = nil,
         names = [_namedRegistries keyEnumerator];
 
-    while (name = [names nextObject])
+    while ((name = [names nextObject]) !== nil)
         [[_namedRegistries objectForKey:name] removeObserver:anObserver object:nil];
 
     [_unnamedRegistry removeObserver:anObserver object:nil];
@@ -122,7 +122,7 @@ var CPNotificationDefaultCenter = nil;
         var name = nil,
             names = [_namedRegistries keyEnumerator];
 
-        while (name = [names nextObject])
+        while ((name = [names nextObject]) !== nil)
             [[_namedRegistries objectForKey:name] removeObserver:anObserver object:anObject];
 
         [_unnamedRegistry removeObserver:anObserver object:anObject];
@@ -225,7 +225,7 @@ var _CPNotificationCenterPostNotification = function(/* CPNotificationCenter */
             keys = [_objectObservers keyEnumerator];
 
         // Iterate through every set of observers
-        while (key = [keys nextObject])
+        while ((key = [keys nextObject]) !== nil)
         {
             var observers = [_objectObservers objectForKey:key],
                 observer = nil,

Foundation/CPPredicate/CPComparisonPredicate.j

@@ -512,9 +512,10 @@ var CPComparisonPredicateModifier,
             result = (_modifier == CPAllPredicateModifier),
             value;
 
-        while (value = [e nextObject])
+        while ((value = [e nextObject]) !== nil)
         {
             var eval = [self _evaluateValue:value rightValue:rightValue];
+
             if (eval != result)
                 return eval;
         }

Foundation/CPPredicate/_CPAggregateExpression.j

@@ -59,7 +59,7 @@
         collection  = [_aggregate objectEnumerator],
         exp;
 
-    while (exp = [collection nextObject])
+    while ((exp = [collection nextObject]) !== nil)
     {
         var eval = [exp expressionValueWithObject:object context:context];
         [eval_array addObject:eval];

Foundation/CPSet+KVO.j

@@ -23,6 +23,7 @@
 @import "CPException.j"
 @import "CPObject.j"
 @import "CPSet.j"
+@import "_CPCollectionKVCOperators.j"
 
 @implementation CPObject (CPSetKVO)
 
@@ -218,7 +219,8 @@
     {
         var object,
             objectEnumerator = [objects objectEnumerator];
-        while (object = [objectEnumerator nextObject])
+
+        while ((object = [objectEnumerator nextObject]) !== nil)
             _add(_proxyObject, _addSEL, object);
     }
     else
@@ -237,7 +239,8 @@
     {
         var object,
             objectEnumerator = [aSet objectEnumerator];
-        while (object = [objectEnumerator nextObject])
+
+        while ((object = [objectEnumerator nextObject]) !== nil)
             _add(_proxyObject, _addSEL, object);
     }
     else
@@ -273,7 +276,8 @@
     {
         var object,
             objectEnumerator = [aSet objectEnumerator];
-        while (object = [objectEnumerator nextObject])
+
+        while ((object = [objectEnumerator nextObject]) !== nil)
             _remove(_proxyObject, _removeSEL, object);
     }
     else
@@ -295,7 +299,8 @@
     {
         var object,
             objectEnumerator = [objects objectEnumerator];
-        while (object = [objectEnumerator nextObject])
+
+        while ((object = [objectEnumerator nextObject]) !== nil)
             _remove(_proxyObject, _removeSEL, object);
     }
     else
@@ -317,7 +322,8 @@
     {
         var object,
             objectEnumerator = [[[self _representedObject] copy] objectEnumerator];
-        while (object = [objectEnumerator nextObject])
+
+        while ((object = [objectEnumerator nextObject]) !== nil)
             _remove(_proxyObject, _removeSEL, object);
     }
     else
@@ -381,7 +387,10 @@
 
 - (id)valueForKeyPath:(CPString)aKeyPath
 {
-    if (aKeyPath.indexOf("@") === 0)
+    if (!aKeyPath)
+        [self valueForUndefinedKey:@"<empty path>"];
+
+    if (aKeyPath.charAt(0) === "@")
     {
         var dotIndex = aKeyPath.indexOf("."),
             operator,
@@ -395,10 +404,7 @@
         else
             operator = aKeyPath.substring(1);
 
-        if (kvoOperators[operator])
-            return kvoOperators[operator](self, _cmd, parameter);
-
-        return nil;
+        return [_CPCollectionKVCOperator performOperation:operator withCollection:self propertyPath:parameter];
     }
     else
     {
@@ -406,12 +412,17 @@
             containedObject,
             containedObjectValue,
             containedObjectEnumerator = [self objectEnumerator];
-        while (containedObject = [containedObjectEnumerator nextObject])
+
+        while ((containedObject = [containedObjectEnumerator nextObject]) !== nil)
         {
             containedObjectValue = [containedObject valueForKeyPath:aKeyPath];
-            if (containedObjectValue)
-                [valuesForKeySet addObject:containedObjectValue];
+
+            if (containedObjectValue === nil || containedObjectValue === undefined)
+                containedObjectValue = [CPNull null];
+
+            [valuesForKeySet addObject:containedObjectValue];
         }
+
         return valuesForKeySet;
     }
 }
@@ -420,108 +431,9 @@
 {
     var containedObject,
         containedObjectEnumerator = [self objectEnumerator];
-    while (containedObject = [containedObjectEnumerator nextObject])
+
+    while ((containedObject = [containedObjectEnumerator nextObject]) !== nil)
         [containedObject setValue:aValue forKey:aKey];
 }
 
 @end
-
-var kvoOperators = [];
-
-// FIXME: this is not DRY because the implementation in CPArray+KVO is merely the same!
-// HACK: prevent these from becoming globals. workaround for obj-j "function foo(){}" behavior
-var avgOperator,
-    maxOperator,
-    minOperator,
-    countOperator,
-    sumOperator;
-
-kvoOperators["avg"] = function avgOperator(self, _cmd, param)
-{
-    //CPSet returns a CPSet - to obtain an array call allObjects
-    var objects = [[self valueForKeyPath:param] allObjects],
-        length = [objects count],
-        index = length,
-        average = 0.0;
-
-    if (!length)
-        return 0;
-
-    while (index--)
-        average += [objects[index] doubleValue];
-
-    return average / length;
-}
-
-kvoOperators["max"] = function maxOperator(self, _cmd, param)
-{
-    //CPSet returns a CPSet - to obtain an array call allObjects
-    var objects = [[self valueForKeyPath:param] allObjects],
-        index = [objects count] - 1,
-        max = [objects lastObject];
-
-    while (index--)
-    {
-        var item = objects[index];
-        if ([max compare:item] < 0)
-            max = item;
-    }
-
-    return max;
-}
-
-kvoOperators["min"] = function minOperator(self, _cmd, param)
-{
-    //CPSet returns a CPSet - to obtain an array call allObjects
-    var objects = [[self valueForKeyPath:param] allObjects],
-        index = [objects count] - 1,
-        min = [objects lastObject];
-
-    while (index--)
-    {
-        var item = objects[index];
-        if ([min compare:item] > 0)
-            min = item;
-    }
-
-    return min;
-}
-
-kvoOperators["count"] = function countOperator(self, _cmd, param)
-{
-    return [self count];
-}
-
-kvoOperators["sum"] = function sumOperator(self, _cmd, param)
-{
-    //CPSet returns a CPSet - to obtain an array call allObjects
-    var objects = [[self valueForKeyPath:param] allObjects],
-        index = [objects count],
-        sum = 0.0;
-
-    while (index--)
-        sum += [objects[index] doubleValue];
-
-    return sum;
-}
-
-
-@implementation CPSet (CPKeyValueObserving)
-
-- (void)addObserver:(id)observer forKeyPath:(CPString)aKeyPath options:(unsigned)options context:(id)context
-{
-    if ([isa instanceMethodForSelector:_cmd] === [CPSet instanceMethodForSelector:_cmd])
-        [CPException raise:CPInvalidArgumentException reason:"Unsupported method on CPSet"];
-    else
-        [super addObserver:observer forKeyPath:aKeyPath options:options context:context];
-}
-
-- (void)removeObserver:(id)observer forKeyPath:(CPString)aKeyPath
-{
-    if ([isa instanceMethodForSelector:_cmd] === [CPSet instanceMethodForSelector:_cmd])
-        [CPException raise:CPInvalidArgumentException reason:"Unsupported method on CPSet"];
-    else
-        [super removeObserver:observer forKeyPath:aKeyPath];
-}
-
-@end

Foundation/CPURLConnection.j

@@ -106,7 +106,7 @@ var CPURLConnectionDelegate = nil;
             key = nil,
             keys = [fields keyEnumerator];
 
-        while (key = [keys nextObject])
+        while ((key = [keys nextObject]) !== nil)
             request.setRequestHeader(key, [fields objectForKey:key]);
 
         request.send([aRequest HTTPBody]);
@@ -196,7 +196,7 @@ var CPURLConnectionDelegate = nil;
             key = nil,
             keys = [fields keyEnumerator];
 
-        while (key = [keys nextObject])
+        while ((key = [keys nextObject]) !== nil)
             _HTTPRequest.setRequestHeader(key, [fields objectForKey:key]);
 
         _HTTPRequest.send([_request HTTPBody]);

Foundation/CPWebDAVManager.j

@@ -84,7 +84,7 @@ CPWebDAVManagerNonCollectionResourceType    = 0;
             URLString = nil,
             URLStrings = [response keyEnumerator];
 
-        while (URLString = [URLStrings nextObject])
+        while ((URLString = [URLStrings nextObject]) !== nil)
         {
             var URL = [CPURL URLWithString:URLString],
                 properties = [response objectForKey:URLString];

Foundation/_CPCollectionKVCOperators.j

@@ -0,0 +1,118 @@
+/*
+ * _CPCollectionKVCOperators.j
+ * Foundation
+ *
+ * Created by Aparajita Fishman.
+ * Copyright 2012 Cappuccino Foundation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+@implementation _CPCollectionKVCOperator : CPObject
+
++ (id)performOperation:(CPString)operator withCollection:(id)aCollection propertyPath:(CPString)propertyPath
+{
+    var selector = CPSelectorFromString(operator + @"ForCollection:propertyPath:");
+
+    if (![self respondsToSelector:selector])
+        return [aCollection valueForUndefinedKey:@"@" + operator];
+
+    return [self performSelector:selector withObject:aCollection withObject:propertyPath];
+}
+
++ (double)avgForCollection:(id)aCollection propertyPath:(CPString)propertyPath
+{
+    if (!propertyPath)
+        return [aCollection valueForUndefinedKey:@"@avg"];
+
+    var objects = [aCollection valueForKeyPath:propertyPath],
+        average = 0.0,
+        enumerator = [objects objectEnumerator],
+        object;
+
+    while ((object = [enumerator nextObject]) !== nil)
+        average += [object doubleValue];
+
+    return average / [objects count];
+}
+
++ (double)minForCollection:(id)aCollection propertyPath:(CPString)propertyPath
+{
+    if (!propertyPath)
+        return [aCollection valueForUndefinedKey:@"@min"];
+
+    var objects = [aCollection valueForKeyPath:propertyPath];
+
+    if ([objects count] === 0)
+        return nil;
+
+    var enumerator = [objects objectEnumerator],
+        min = [enumerator nextObject],
+        object;
+
+    while ((object = [enumerator nextObject]) !== nil)
+    {
+        if ([min compare:object] > 0)
+            min = object;
+    }
+
+    return min;
+}
+
++ (double)maxForCollection:(id)aCollection propertyPath:(CPString)propertyPath
+{
+    if (!propertyPath)
+        return [aCollection valueForUndefinedKey:@"@max"];
+
+    var objects = [aCollection valueForKeyPath:propertyPath];
+
+    if ([objects count] === 0)
+        return nil;
+
+    var enumerator = [objects objectEnumerator],
+        max = [enumerator nextObject],
+        object;
+
+    while ((object = [enumerator nextObject]) !== nil)
+    {
+        if ([max compare:object] < 0)
+            max = object;
+    }
+
+    return max;
+}
+
++ (double)sumForCollection:(id)aCollection propertyPath:(CPString)propertyPath
+{
+    if (!propertyPath)
+        return [aCollection valueForUndefinedKey:@"@sum"];
+
+    var objects = [aCollection valueForKeyPath:propertyPath],
+        sum = 0.0,
+        enumerator = [objects objectEnumerator],
+        object;
+
+    while ((object = [enumerator nextObject]) !== nil)
+        sum += [object doubleValue];
+
+    return sum;
+}
+
++ (int)countForCollection:(id)aCollection propertyPath:(CPString)propertyPath
+{
+    return [aCollection count];
+}
+
+@end

Tests/Foundation/CPKVCArrayTest.j

@@ -2,8 +2,9 @@ var COUNTER;
 
 @implementation CPKVCArrayTest : OJTestCase
 {
-    TestObject                          _object @accessors(property=object);
-    ImplementedTestObject               _implementedObject @accessors(property=implementedObject);
+    TestObject              _object @accessors(property=object);
+    ImplementedTestObject   _implementedObject @accessors(property=implementedObject);
+    CPArray                 _kvcArray @accessors(property=kvcArray);
 }
 
 - (void)setUp
@@ -298,11 +299,45 @@ var COUNTER;
          message:@"replaceObjectInValuesAtIndexes:withValues: should have been called once"];
 }
 
+- (void)testKVCArrayOperators
+{
+    var one = [1, 1, 1, 1, 1, 1, 1, 1],
+        two = [1, 2, 3, 4, 8, 0];
+
+    [self assert:[one valueForKey:"@count"] equals:8];
+    [self assert:[one valueForKeyPath:"@sum.intValue"] equals:8];
+    [self assert:[two valueForKeyPath:"@avg.intValue"] equals:3];
+    [self assert:[two valueForKeyPath:"@max.intValue"] equals:8];
+    [self assert:[two valueForKeyPath:"@min.intValue"] equals:0];
+
+    var a = [A new];
+    [a setValue:one forKey:"b"];
+    [self assert:[a valueForKeyPath:"b.@count"] equals:8];
+    [self assert:[a valueForKeyPath:"b.@sum.intValue"] equals:8];
+
+    var b = [];
+    [b addObject:[CPDictionary dictionaryWithObjects:[@"Tom", 27] forKeys:[@"name", @"age"]]];
+    [b addObject:[CPDictionary dictionaryWithObjects:[@"Dick", 31] forKeys:[@"name", @"age"]]];
+    [b addObject:[CPDictionary dictionaryWithObjects:[@"Harry", 47] forKeys:[@"name", @"age"]]];
+    [self assert:[b valueForKeyPath:@"@sum.age"] equals:105];
+    [self assert:[b valueForKeyPath:@"@avg.age"] equals:35];
+    [self assert:[b valueForKeyPath:@"@min.age"] equals:27];
+    [self assert:[b valueForKeyPath:@"@max.age"] equals:47];
+    [self assert:[b valueForKeyPath:@"@min.name"] equals:@"Dick"];
+    [self assert:[b valueForKeyPath:@"@max.name"] equals:@"Tom"];
+}
+
+@end
+
+@implementation A : CPObject
+{
+    id  b;
+}
 @end
 
 @implementation TestObject : CPObject
 {
-    CPArray                     _values @accessors(property=values);
+    CPArray _values @accessors(property=values);
 }
 
 - (id)init
@@ -393,4 +428,4 @@ var COUNTER;
     [[self values] replaceObjectsAtIndexes:theIndexes withObjects:theObjects];
 }
 
-@end
+@end

Tests/Foundation/CPKVOTest.j

@@ -382,23 +382,6 @@
     [self assertTrue: _sawObservation message:"Never recieved an observation"];
 }
 
-- (void)testKVCArrayOperators
-{
-    var one = [1, 1, 1, 1, 1, 1, 1, 1],
-        two = [1, 2, 3, 4, 8, 0];
-
-    [self assert:[one valueForKey:"@count"] equals:8];
-    [self assert:[one valueForKeyPath:"@sum.intValue"] equals:8];
-    [self assert:[two valueForKeyPath:"@avg.intValue"] equals:3];
-    [self assert:[two valueForKeyPath:"@max.intValue"] equals:8];
-    [self assert:[two valueForKeyPath:"@min.intValue"] equals:0];
-
-    var a = [A new];
-    [a setValue:one forKey:"b"];
-    [self assert:[a valueForKeyPath:"b.@count"] equals:8];
-    [self assert:[a valueForKeyPath:"b.@sum.intValue"] equals:8];
-}
-
 - (void)testPerformance
 {
     bob = [PersonTester new];

Tests/Foundation/CPKeyValueCodingTest.j

@@ -232,7 +232,7 @@ var accessIVARS = YES;
         value,
         keyEnumerator = [dictForKeys keyEnumerator];
 
-    while (key = [keyEnumerator nextObject])
+    while ((key = [keyEnumerator nextObject]) !== nil)
     {
         value = [dictForKeys objectForKey: key];
         [self assert: [kvcTestObject valueForKey: key] same: value];
@@ -384,7 +384,8 @@ var accessIVARS = YES;
     var key,
         aValue,
         keyEnumerator = [dictForKeys keyEnumerator];
-    while (key = [keyEnumerator nextObject])
+
+    while ((key = [keyEnumerator nextObject]) !== nil)
     {
         aValue = [dictForKeys objectForKey: key];
         [self assert: [kvcTestObject valueForKey: key] same: aValue];
@@ -417,7 +418,7 @@ var accessIVARS = YES;
         value,
         keyEnumerator = [dictForKeys keyEnumerator];
 
-    while (key = [keyEnumerator nextObject])
+    while ((key = [keyEnumerator nextObject]) !== nil)
     {
         value = [dictForKeys objectForKey: key];
         [self assert: [CPNull null] same:value ];

Tests/Foundation/CPSetTest.j

@@ -235,4 +235,30 @@
     [self assertSet:set onlyHasObjects:["horizon", "surfer", "7"]];
 }
 
+- (void)testKVCSetOperators
+{
+    var one = [CPSet setWithArray:[@"one", @"two", @"three"]],
+        two = [CPSet setWithArray:[1, 2, 3, 4, 8, 0]];
+
+    [self assert:[one valueForKey:"@count"] equals:3];
+    [self assert:[two valueForKey:"@count"] equals:6];
+    [self assert:[two valueForKeyPath:"@sum.intValue"] equals:18];
+    [self assert:[two valueForKeyPath:"@avg.doubleValue"] equals:3.0];
+    [self assert:[one valueForKeyPath:"@max.description"] equals:@"two"];
+    [self assert:[two valueForKeyPath:"@max.intValue"] equals:8];
+    [self assert:[one valueForKeyPath:"@min.description"] equals:@"one"];
+    [self assert:[two valueForKeyPath:"@min.intValue"] equals:0];
+
+    var b = [CPSet set];
+    [b addObject:[CPDictionary dictionaryWithObjects:[@"Tom", 27] forKeys:[@"name", @"age"]]];
+    [b addObject:[CPDictionary dictionaryWithObjects:[@"Dick", 31] forKeys:[@"name", @"age"]]];
+    [b addObject:[CPDictionary dictionaryWithObjects:[@"Harry", 47] forKeys:[@"name", @"age"]]];
+    [self assert:[b valueForKeyPath:@"@sum.age"] equals:105];
+    [self assert:[b valueForKeyPath:@"@avg.age"] equals:35];
+    [self assert:[b valueForKeyPath:@"@min.age"] equals:27];
+    [self assert:[b valueForKeyPath:@"@max.age"] equals:47];
+    [self assert:[b valueForKeyPath:@"@min.name"] equals:@"Dick"];
+    [self assert:[b valueForKeyPath:@"@max.name"] equals:@"Tom"];
+}
+
 @end

Tools/capp/Configuration.j

@@ -189,7 +189,7 @@ function config(/*va_args*/)
         var key = nil,
             keyEnumerator = [configuration storedKeyEnumerator];
 
-        while (key = [keyEnumerator nextObject])
+        while ((key = [keyEnumerator nextObject]) !== nil)
             print(key + '=' + [configuration valueForKey:key]);
     }
     else if (action === "get")

Tools/capp/Generate.j

@@ -166,7 +166,7 @@ function gen(/*va_args*/)
                     key = null,
                     keyEnumerator = [configuration keyEnumerator];
 
-                while (key = [keyEnumerator nextObject])
+                while ((key = [keyEnumerator nextObject]) !== nil)
                     contents = contents.replace(new RegExp("__" + RegExp.escape(key) + "__", 'g'), [configuration valueForKey:key]);
 
                 FILE.write(path, contents, { charset: "UTF-8"});

Tools/nib2cib/NSNibConnector.j

@@ -133,7 +133,7 @@ var NSTransformers = [CPSet setWithObjects:
             keyEnumerator = [NSOptions keyEnumerator],
             key;
 
-        while (key = [keyEnumerator nextObject])
+        while ((key = [keyEnumerator nextObject]) !== nil)
         {
             var CPKey = @"CP" + key.substring(2),
                 NSValue = [NSOptions objectForKey:key];

Tools/nib2cib/NSToolbar.j

@@ -45,7 +45,7 @@
 
         // Some of the item identifiers will be changed when loaded by NSToolbarItem, so we must change
         // the map to correspond.
-        while (key = [keyEnumerator nextObject])
+        while ((key = [keyEnumerator nextObject]) !== nil)
         {
             var transformedKey = NS_CPToolbarItemIdentifierMap[key] || key;
             [_identifiedItems setObject:[nsIdentifiedItems objectForKey:key] forKey:transformedKey];