1 files changed, 53 insertions, 0 deletions
diff --git a/Foundation/GTMNSEnumerator+Filter.h b/Foundation/GTMNSEnumerator+Filter.h
new file mode 100644
index 0000000..8e10d93
--- /dev/null
+++ b/Foundation/GTMNSEnumerator+Filter.h
@@ -0,0 +1,53 @@
+//
+//  GTMNSEnumerator+Filter.h
+//
+//  Copyright 2007-2008 Google Inc.
+//
+//  Licensed under the Apache License, Version 2.0 (the "License"); you may not
+//  use this file except in compliance with the License.  You may obtain a copy
+//  of the License at
+// 
+//  http://www.apache.org/licenses/LICENSE-2.0
+// 
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+//  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+//  License for the specific language governing permissions and limitations under
+//  the License.
+//
+
+#import <Foundation/Foundation.h>
+
+/// A generic category for methods that allow us to filter enumeratable
+/// containers, inspired by C++ Standard Library's use of iterators.
+/// Like in C++, these assume the underlying container is not modified during
+/// the lifetime of the iterator.
+///
+@interface NSEnumerator (GTMEnumeratorFilterAdditions)
+
+/// @argument predicate - the function return BOOL. will be applied to each element
+/// @argument argument - optional argument to pass to predicate
+/// @returns an enumerator that contains only elements where [element sel:argument] is true
+- (NSEnumerator *)gtm_filteredEnumeratorByMakingEachObjectPerformSelector:(SEL)predicate
+                                                               withObject:(id)argument;
+
+/// @argument selector - the function return a transformed object. will be applied to each element
+/// @argument argument - optional argument to pass to transformer
+/// @returns an enumerator that contains the transformed elements
+- (NSEnumerator *)gtm_enumeratorByMakingEachObjectPerformSelector:(SEL)selector
+                                                       withObject:(id)argument;
+
+/// @argument target - receiver for each method
+/// @argument predicate - as  in, [target predicate: [self nextObject]], return a BOOL
+/// @returns an enumerator that contains only elements where [element sel:argument] is true
+- (NSEnumerator *)gtm_filteredEnumeratorByTarget:(id)target
+                           performOnEachSelector:(SEL)predicate;
+
+/// @argument target - receiver for each method
+/// @argument sel - as  in, [target selector: [self nextObject]], return a transformed object
+/// @returns an enumerator that contains the transformed elements
+- (NSEnumerator *)gtm_enumeratorByTarget:(id)target
+                   performOnEachSelector:(SEL)selector;
+
+@end
+