I have four macs at home and would like to be able to keep them in perfect sync at all times. I propose a network service which uses Bonjour to detect the peers, kernel file change notifications to detect file modification and a variant of rsync (has to support xattrs) to synchronize the data along with smart presence detection to lock displays which I'm not using. Features would include:

• Select peers to include in lockstep group
• Select files and folders to include and exclude
• Select patterns to exclude ala CVSIGNORE
• Keep peers in live sync via kernel file change notification
• Lock screens of other peers when I login to one machine
• Track changes on a disconnected laptop when returned
• Conflict detection and resolution
• Status menu interface with status indication

This would allow me to put a bullet through my PowerBook, go right to my iMac and keep working right where I left off. Better than backup, it's live sync made simple.

Washington post, not bad at all, always wanted to be in print.

The secret is to use Key Value Coding, the Cocoa technology which provides a degree of introspection support for NSObjects, very similar to the way the java.lang.reflect classes do for Java Beans. Here is a simple mutable accessor declaration ripped from the RSRadio class in iStumbler:

        - (NSString*) name;
        - (void) setName:(NSString*)mac;
        

Simple. This corresponds to the getName()/setName(String name) pair you would put into a Java Bean, so far that's nice and simple and easy to grok. Now let's assume we've got a bunch of these methods for the various properties of an object, and let's further say that we've got a dictionary of properties we would also like to expose to the table view. RSRadio has a member NSDictionary* radio_props in which we store the uncommonalities between AirPort and Bluetooth radios, here's the implementation of valueForUndefinedKey: which allows KVC to access properties of that dictionary if there is no accessor available:

        - (id) valueForUndefinedKey:(NSString*) key
        {
            return [radio_props valueForKey:key];
        }
        

Again, blissfully simple. Note that this implementation does hide some errors, if you provide a key that's not in the dictionary is just returns nil as NSDictionary would, which is fine for our purposes. Now all we need is a NSTableDataSource which can make use of the KVC properties in our object:

        // RSStoreTable.h
        
        @interface RSStoreTable : NSObject 
        {
            RSStore* store;
            NSString* type;
        }

        // RSStoreTable.m

        - (int) numberOfRowsInTableView:(NSTableView*) theTable
        {
            if ( type)
                return [store countRadiosOfType:type];
            else
                return [store countRadios];
        }

        - (id) tableView:(NSTableView*) table objectValueForTableColumn:(NSTableColumn*) column row:(int) row
        {
            id value;
            
            @try
            {
                NSArray* radios = (type ? [store radiosOfType:type] : [store radios]);
                if (row > [radios count]) // we don't have a radio to display
                    @throw [NSException exceptionWithName:@"invalid row" reason:@"row > radios" userInfo:nil];
                NSMutableArray* sorted = [[radios mutableCopy] autorelease];
                if ([[table sortDescriptors] count] > 0) // TODO save the sorted array
                    [sorted sortUsingDescriptors:[table sortDescriptors]];
                RSRadio* radio = [sorted objectAtIndex:row];
                value = [radio valueForKeyPath:[column identifier]];
            }
            @catch (NSException* reason)
            {
                NSLog( @"WARNING exception in RSStoreTable: %@\n", reason);
                value = @"!";
            }
            
            return value;
        }
        

Now, in interface builder you can simply set the NSTableColumns identifier and sort descriptor to any KVC property of your object and presto! You've got a dynanic table view which you won't have to write another line of code to use. Plus, if something does go wrong you've got a place to set breakpoints and the ability to inspect exactly what your data-source is doing. Also this code check for exceptions and DOESN'T CRASH YOUR APP, just politely logs an error message.

I'm still For Hire if you're looking for a seasoned (with at touch of habanero) cocoa developer with two shipping apps under his belt.