libObjCAttr - attributes for your code

libObjCAttr is attribute-oriented programming for Objective-C language. It is compile-time based with the support of Xcode auto-completion and errors tracing features. We nailed every aspect of the implementation including performance, so attributes will never be a bottleneck.

Our solution helps reduce the complexity of code, makes it compact and self-documented. There are a lot of languages with attributes support, we added Objective-C into that list.

Installation

CocoaPods is the only recommended way of libObjCAttr integration. Besides standard configuration of pod dependencies, pod_install hook is required as shown below. A typical Podfile will look as follows:

pod 'libObjCAttr'

post_install do |installer|
    require File.expand_path('ROADConfigurator.rb', './Pods/libObjCAttr/libObjCAttr/Resources/')
    ROADConfigurator::post_install(installer)
end

Note: If you want to get rid of warning from Xcodeproj gem, copy-paste and run in terminal next command before running pod install:

export COCOAPODS_DISABLE_DETERMINISTIC_UUIDS=YES

Samples

It is super easy to mark your code with an attribute. We currently support 4 types of attributes:

• Class attributes
• IVar attributes
• Method attributes
• Property attributes

Check out this example to get to know how to declare them:

RF_ATTRIBUTE(MyAttribute, stringProperty = @"Hello world")
@interface AnnotatedClass : NSObject {

    RF_ATTRIBUTE(MyAttribute, numericProperty = @9000)
    NSObject * _someField;
}

RF_ATTRIBUTE(MyAttribute, blockProperty = ^(int value) { return value; })
- (void)foo;

RF_ATTRIBUTE(MyAttribute, objectProperty = [NSObject new])
@property NSString *name;

@end

An attribute can be any class inherited from NSObject or its subclasses. It may or may not have properties.

#import <ROAD/ROADAttribute.h>

@interface MyAttribute : NSObject

@property NSString *stringProperty;
@property NSNumber *numericProperty;
@property (copy) id blockProperty;
@property id objectProperty;

@end

Now you can get them in runtime with code like this:

...

NSArray *classAttributes = [AnnotatedClass RF_attributesForClass];
NSArray *ivarAttributes = [AnnotatedClass RF_attributesForIvar:@"_someField"];

// Let's filter it, in case there are many of them
MyAttribute *methodAttributes = [AnnotatedClass RF_attributeForMethod:@"foo" withAttributeType:[MyAttribute class]];
MyAttribute *classAttributes = [AnnotatedClass RF_attributeForProperty:@"name" withAttributeType:[MyAttribute class]];

...

Also check out an info about an attribute generator, that makes all behind the scene magic.

Requirements

libObjCAttr requires iOS 5.0 and above. The compatibility with 4.3 and older is not tested.

libObjCAttr was initially designed to use ARC.

Solutions powerd by LibObjCAttr

• ROAD Framework — https://github.com/epam/road-ios-framework
• Add your project here ;)

Contact

Follow LibObjCAttr on Twitter (@LibObjCAttr)

License

libObjCAttr is made available under the terms of the BSD-3. Open the LICENSE file that accompanies this distribution to see the full text of the license.

Contribution

There are three ways you can help us:

• Raise an issue. You found something that does not work as expected? Let us know about it.
• Suggest a feature. It's even better if you come up with a new feature and write us about it.
• Write some code. We would love to see more pull requests to our framework, just make sure you have the latest sources.