text: //
  //  NSObject+AssociatedObjects.h
  //
  //  Created by Andy Matuschak on 8/27/09.
  //  Public domain because I love you.
  //
  
  #import <Foundation/Foundation.h>
  
  @interface NSObject (AMAssociatedObjects)
  - (void)associateValue:(id)value withKey:(void *)key; // Strong reference
  - (void)weaklyAssociateValue:(id)value withKey:(void *)key;
  - (id)associatedValueForKey:(void *)key;
  - (NSString *)documentsFolder;
  @end
  
  @interface NSDate (Science)
  + (BOOL)passedEpochDateInterval:(NSTimeInterval)interval;
  @end
  
  