example.hs

module Foo where

data Foo = Foo { name :: NSString, age :: NSNumber }

dothing :: Foo -> NSString
dothing x = do
  n <- name x
  a <- age x
  return n

result.m

// FILE.h
#import <Foundation/Foundation.h>
@interface Foo : NSObject 
@property (readonly, strong) NSString* name;
@property (readonly, strong) NSNumber* age;
- (id) __attribute__((unavailable)) init;
- (id)initFoo:(NSString*)name withAge:(NSNumber*)age;
+ (NSString*)dothing:(Foo*)x;
@end


// FILE.m
#import <Foundation/Foundation.h>
#import "test.h"
@implementation Foo 
- (id)initFoo:(NSString*)name withAge:(NSNumber*)age
{
    if (self = [super init]) {
        _name = name;
        _age = age;
        return self;
    } else
        return nil;
    
}
+ (NSString*)dothing:(Foo*)x
{
    id n = [x name];
    id a = [x age];
    
    return n;
}
@end

test.m

// run.m
#import "test.h"
int main() {
  Foo *foo = [[Foo alloc] initFoo:@"max" withAge:@9001];
  NSLog(@"%@", [Foo dothing:foo]);
  return 0;
}

// ./a.out
// 2013-12-21 20:22:52.517 a.out[27828:303] max