Python's os.path.join, for Objective-C

join.m

#import <Foundation/Foundation.h>
#import <stdarg.h>

@interface NSString (Paths)
+ (NSString *)stringByJoiningPathComponents:(NSString *)part, ...;
@end

@implementation NSString (Paths)
+ (NSString *)stringByJoiningPathComponents:(NSString *)part, ...
{
    NSString *path = [NSString stringWithString:part];
    NSString *newPart = nil;
    
    va_list args;
    va_start(args, part);
    while ((newPart = va_arg(args, NSString *)) != nil) {
        path = [newPart isAbsolutePath] ? [NSString stringWithString:newPart] : [path stringByAppendingPathComponent:newPart];
    }
    va_end(args);
    
    return path;
}
@end

int main(int argc, char **argv)
{
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    NSString *path = [NSString stringByJoiningPathComponents:@"/", @"tmp", @"static", @"nybooks.com", nil];
    NSLog(@"%@", path);
    [pool release];
    return 0;
}

Thanks for this function. I have found it useful in the work I have been doing. I wanted to suggest a possible change to it, though, in order to make it work more like Python's os.path.join. If an absolute path is passed in as one of the subsequent arguments, Python will use that path from then on, discarding anything before. To this end, I would do this:

while ((newPart = va_arg(args, NSString *)) != nil) {
if ([newPart isAbsolutePath])
path = [NSString stringWithString:newPart];
else
path = [path stringByAppendingPathComponent:newPart];
}

I don't know how to insert code into comments...

Thanks! I made that modification.