Conceptually similar to a struct, but with object compatibility and memory management.

Record.h

//
//  Record.h
//
//  Created by Benedict Cohen on 10/01/2012.
//  Copyright (c) 2012 Benedict Cohen. All rights reserved.
//
//


/*
 
 A Record is a Block (a.k.a. closure) that returns a struct. Unlike struct, Records handle memory management of their fields.
 The fields can be Objective-C objects or basic C types. Because Records are Blocks they can be treated like objects. 
 
 To declare a Record you must define its fields and implement a function for creating an instance of the record. 2 types are
 available once a record has been declare:
    - A struct that contains the defined fields
    - A block that takes zero arguments and returns a struct 
 
 Declaration example
 ===================
 //Person Record declaration
 RECORD(Person,
 RECORD_FIELD_OBJ(NSString *name)
 RECORD_FIELD_PRM(float age)
 );

 
 ////////The above declaration results in the follow code:
 //Person
 typedef struct Person_
 {
     __unsafe_unretained NSString *name;
     float age;
 } Person;
 
 
 //PersonRecord
 typedef Person(^PersonRecord)(void);
 ////////
 
 
 
 
 
 The creation function must return a Record. All object fields must be captured inside the returned block.
 
 
 Creation function example
 =========================
 static PersonRecord createPersonRecord(NSString *name, float age)
 {
     PersonRecord spartacus = ^(void) {
         Person p;
         p.name = name;
         p.age = age;
         return p;
     };
 
    //for ARC code
    return spartacus;
 
    //for non-ARC code
    //return (PersonRecord)[[spartacus copy] autorelease];
 }

 
 Useage example
 ==============
  
 PersonRecord bill    = createPersonRecord(@"Bill Wyman",     75);
 PersonRecord charlie = createPersonRecord(@"Charlie Wattts", 70);
 PersonRecord keith   = createPersonRecord(@"Keith Richards", 68);
 PersonRecord mick    = createPersonRecord(@"Mick Jagger",    68);
 PersonRecord ronnie  = createPersonRecord(@"Ronnie Wood",    64);

 NSArray *stones = [NSArray arrayWithObjects: bill, charlie, keith, mick, ronnie, nil];
 
 
 for (PersonRecord stone in stones)
 {
     Person p = stone(); 
     NSLog(@"%@  %f", p.name, p.age);
 }
 
 
 It's worth noting that the creation function has the potentinal to do interesting things.
 
 */



#import <Foundation/Foundation.h>



#define RECORD_FIELD_OBJ(FIELD_TYPE_AND_NAME...) __unsafe_unretained FIELD_TYPE_AND_NAME;
#define RECORD_FIELD_PRM(FIELD_TYPE_AND_NAME...) FIELD_TYPE_AND_NAME;


#define RECORD(RECORD_NAME, FIELDS...) \
\
/*Typedef for struct returned by Record */ \
typedef struct RECORD_NAME ## _ \
{ \
    FIELDS \
} RECORD_NAME; \
\
\
\
/*typedef of Record that returns struct*/ \
typedef RECORD_NAME(^RECORD_NAME ## Record)(void);