use Objective-C in Linux environment

.gitignore

a.out
*.o
*.d

Animal.h

#import <Foundation/Foundation.h>

@interface Animal : NSObject {
@public
    NSString *name;
}
-(id)setName: (NSString *)n;
-(id)name;
@end

Animal.m

#import "Animal.h"

@implementation Animal

-(id)setName: (NSString *)n {
    name = n;
    return self;
}

-(id)name {
    return name;
}

@end

Face.h

#import <Foundation/Foundation.h>

@interface Face : NSObject {
NSString *name;
}
@property (nonatomic, copy) NSString *name;
@end

Face.m

#import "Face.h"

@implementation Face

@synthesize name;

@end

Hello.h

#import <Foundation/Foundation.h>

@interface Hello : NSObject {
@public
    int numerator;
    int denominator;
    NSString *string;
}

-(Hello*)initWithString: (NSString*)str;
-(void)hello ;
-(id)echo: (id)str;
-(id)setNumerator: (int)n;
-(id)setDenominator: (int)d;
-(id)setString: (NSString*)str;
-(id)string;

@end

Hello.m

#import "Hello.h"

@implementation Hello : NSObject

-(Hello*)initWithString: (NSString*)str {
    self = [super init];
    [self setString:str];
    return self;
}

-(void)hello {
    NSLog(@"hello");
}

-(id)echo: (id)str {
    return str;
}

-(id)setNumerator: (int)n {
    numerator = n;
    return self;
}

-(id)setDenominator: (int)d {
    denominator = d;
    return self;
}

-(id)setString: (NSString*)str {
    [str retain];
    [string release];
    string = str;
    return self;
}

-(id)string {
    return string;
}

@end

main.m

#import <Foundation/Foundation.h>
#import "Animal.h"
#import "Hello.h"
#import "Face.h"

@protocol Fly
-(NSString*) fly;
@end

@interface Bird : NSObject <Fly> {
    NSString *name;
}
-(NSString*) name;
-(id) setName: (NSString*)n;
@end

@implementation Bird
-(NSString*) fly {
    return @"is a bird can fly (protocol)";
}
-(NSString*) name {
    return name;
}
-(id) setName: (NSString*)n {
    [n retain];
    [name release];
    name = n;
    return self;
}
@end

@interface Hello (Say)
-(NSString*) say;
@end

@implementation Hello (Say)
-(NSString*) say {
    return @"hello, i am a hello object";
}
@end

int main(int argc, char *argv[]) {

        NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

        Bird *bird = [[Bird alloc] init];
        NSLog(@"%@", [bird fly]);

        [bird setValue:@"lucky" forKey:@"name"];
        [bird setName:@"jennifer"];
        NSLog(@"set name of bird as %@", [bird name]);
        


        // NSString *str = [[NSString alloc] init];
        // NSString *str2 = [NSString new];

        Hello *hello = [[Hello new] autorelease];
        [hello hello];
        NSLog(@"%@", [hello echo:@"echo here"]);
        NSLog(@"%@", [hello say]);

        Hello *hero = [[[Hello alloc] initWithString:@"set set string"] autorelease];
        NSLog(@"%@", [hero string]);

        NSString *init_with_class = [NSString stringWithFormat:@"init with class method here"];
        NSLog(@"%@", init_with_class); // this string is an autorelease one

        [[hello setNumerator:1] setDenominator:3];

        Animal *a = [[Animal new] autorelease];
        [a setName:@"lucky"];
        NSLog(@"%@", [a name]);

        NSNumber *number = [NSNumber numberWithInteger:100];
        NSLog(@"%@", number);

        NSMutableDictionary *hash = [NSMutableDictionary dictionary];
        [hash setObject:@"bar" forKey:@"foo"];
        NSLog(@"%@", hash);

        Face *face = [[Face new] autorelease];
        face.name = @"face two";
        NSLog(@"%@", face.name);
        
        [pool drain];

        return 0;
}

Makefile

FLAG=`gnustep-config --objc-flags`


.PHONY: all clean

all: Animal.o Hello.o Face.o
	gcc $(FLAG) -lgnustep-base main.m *.o

clean: 
	rm a.out *.o *.d

Animal.o: Animal.m
	gcc -c Animal.m $(FLAG) 

Hello.o: Hello.m
	gcc -c Hello.m $(FLAG)

Face.o: Face.m
	gcc -c Face.m $(FLAG)