Add NSObject+BindingValue

NSObject+BindingValue.h

@@ -0,0 +1,20 @@
+//
+//  NSObject+BindingValue.h
+//  Tags
+//
+//  Created by Sven Weidauer on 10.06.11.
+//  Copyright 2011 __MyCompanyName__. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+
+@interface NSObject (BindingValue)
+
+- (void) setValue: (id) value forBinding: (NSString *) binding;
+- (id) valueForBinding: (NSString *) binding;
+
+- (id) mutableArrayValueForBinding: (NSString *) binding;
+- (id) mutableSetValueForBinding: (NSString *) binding;
+
+@end

NSObject+BindingValue.m

@@ -0,0 +1,62 @@
+//
+//  NSObject+BindingValue.m
+//  Tags
+//
+//  Created by Sven Weidauer on 10.06.11.
+//  Copyright 2011 __MyCompanyName__. All rights reserved.
+//
+
+#import "NSObject+BindingValue.h"
+
+
+@implementation NSObject (BindingValue)
+
+static NSValueTransformer *TransformerFromInfoDict( NSDictionary *dict )
+{
+    NSDictionary *options = dict[NSOptionsKey];
+    if (options == nil) return nil;
+    
+    NSValueTransformer *transformer = options[NSValueTransformerBindingOption];
+    
+    if (transformer == nil || (id)transformer == [NSNull null]) {
+        transformer = nil;
+        NSString *name = options[NSValueTransformerNameBindingOption];
+        if (name != nil && (id)name != [NSNull null]) {
+            transformer = [NSValueTransformer valueTransformerForName: name];   
+        }
+    }
+    
+    return transformer;
+}
+
+- (void) setValue: (id) value forBinding: (NSString *) binding;
+{
+    NSDictionary *info = [self infoForBinding: binding];
+    NSValueTransformer *transformer = TransformerFromInfoDict( info );
+    if (transformer != nil && [[transformer class] allowsReverseTransformation]) value = [transformer reverseTransformedValue: value];
+    [info[NSObservedObjectKey] setValue: value forKeyPath: info[NSObservedKeyPathKey]];
+}
+
+- (id) valueForBinding: (NSString *) binding;
+{
+    NSDictionary *info = [self infoForBinding: binding];
+    id value = [info[NSObservedObjectKey] valueForKeyPath: info[NSObservedKeyPathKey]];
+    NSValueTransformer *transformer = TransformerFromInfoDict( info );
+    if (transformer != nil) value = [transformer transformedValue: value];
+    return value;
+}
+
+- (id) mutableArrayValueForBinding: (NSString *) binding;
+{
+    NSDictionary *info = [self infoForBinding: binding];
+    return [info[NSObservedObjectKey] mutableArrayValueForKeyPath: info[NSObservedKeyPathKey]];
+}
+
+- (id) mutableSetValueForBinding: (NSString *) binding;
+{
+    NSDictionary *info = [self infoForBinding: binding];
+    return [info[NSObservedObjectKey] mutableSetValueForKeyPath: info[NSObservedKeyPathKey]];
+}
+
+
+@end