JNCons.h

//
//  JNCons.h
//  AnimationLanguage
//
//  Created by narumij on 11/01/18.
//  Copyright 2011 narumij. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface JNCons : NSObject {
	id car;
	id cdr;
}
@property(nonatomic,retain) id car,cdr;
+(id)cons:(id)car :(id)cdr;
+(id)arrayWithArray:(NSArray*)array;
+(int)allocatingCount;
-(id)last;
-(void)addObject:(id)obj;
-(id)objectAtIndex:(NSUInteger)index;
-(NSString*)description;
-(NSString*)stringValue;
-(NSArray*)array;
@end

#define CONS(car,cdr) [JNCons cons:car :cdr]
#define CAR(cons) [cons car]
#define CDR(cons) [cons cdr]
#define CADR(cons) [[cons cdr] car]
#define CDDR(cons) [[cons cdr] cdr]

JNCons.m

//
//  JNCons.m
//  AnimationLanguage
//
//  Created by narumij on 11/01/18.
//  Copyright 2011 narumij. All rights reserved.
//

#import "JNCons.h"

static int cons_count = 0;

@implementation JNCons
@synthesize car,cdr;
+(id)cons:(id)car :(id)cdr
{
	JNCons *cons = [JNCons new];
	cons.car = car;
	cons.cdr = cdr;
	return [cons autorelease];
}
+(id)arrayWithArray:(NSArray*)array
{
	JNCons *cons = nil;
	for ( id obj in array ) {
		if ( cons == nil )
			cons = CONS( obj, nil );
		else
			[[cons last] setCdr:CONS(obj,nil)];
	}
	return cons;
}
-(NSArray*)array
{
	NSMutableArray *anArray = [NSMutableArray new];
	JNCons *cons = self;
	while ( cons && [cons isKindOfClass:[JNCons class]] ) {
		[anArray addObject:cons.car];
		cons = cons.cdr;
	}
	if ( cons != nil )
		[anArray addObject:cons];
	return anArray;
}
- (id) init
{
	self = [super init];
	if (self != nil) {
		++cons_count;
	}
	return self;
}
- (void) dealloc
{
	--cons_count;
	[super dealloc];
}
+(int)allocatingCount
{
	return cons_count;
}
-(id)last
{
	JNCons *cons = self;
	while ( [cons cdr] && [[cons cdr] isKindOfClass:[JNCons class]])
		cons = [cons cdr];
	return cons;
}
-(void)addObject:(id)obj
{
	if ( self.car == nil )
	{
		self.car = obj;
		return;
	}
	JNCons *last = [self last];
	last.cdr = CONS(obj,nil);
}
-(id)objectAtIndex:(NSUInteger)index
{
	JNCons *cons = self;
	for (int i = 0; i < index; ++i) {
		cons = [cons cdr];
	}
	return [cons car];
}
-(NSString*)stringValue
{
	if ( self.car == nil && self.cdr == nil )
		return @"()";
	NSString *description = @"(";
	JNCons *cons = self;
	int i = 0;
	for ( ; cons && [cons isKindOfClass:[JNCons class]]; ++i, cons = cons.cdr ) {
		description = [description stringByAppendingFormat:
					   i == 0 ? @"%@" : @" %@",
					   [cons.car description]];
	}
	if ( cons != nil )
		return [description stringByAppendingFormat:@". %@)",cons];
	return [description stringByAppendingFormat:@")"];
}
-(NSString*)description
{
	return [NSString stringWithFormat:@"%@ %@",[super description],[self stringValue]];
}

@end