Carefully suggesting a previous location to a save panel

gistfile1.m

NSSavePanel *savePanel = [NSSavePanel savePanel];

NSURL *url = [self mostRecentlySavedToURL];
NSURL *parentDirectory = [url URLByDeletingLastPathComponent];

NSNumber *isDirectory;
if ([parentDirectory getResourceValue:&isDirectory forKey:NSURLIsDirectoryKey error:NULL] &&
    [isDirectory boolValue])
{
    [savePanel setDirectoryURL:parentDirectory];
}

[savePanel setNameFieldStringValue:[url lastPathComponent]];

// Finish configuring and run the save panel