We were having a discussion in the Clearleft office recently about that perennially-tricky navigation pivot: tags. Specifically, we were discussing how to represent the interface for combinatorial tags i.e. displaying results of items that have been tagged with tag A and tag B.
I realised that this was functionality that I wasn’t even offering on Huffduffer, so I set to work on implementing it. I decided to dodge the interface question completely by only offering this functionality through the browser address bar. As a fairly niche, power-user feature, I’m not sure it warrants valuable interface real estate—though I may revisit that challenge later.
I can’t use the + symbol as a tag separator because Huffduffer allows spaces in tags (and spaces are converted to pluses in URLs), so I’ve settled on commas instead.
For example, there are plenty of items tagged with “music” (/tags/music) and plenty of items tagged with “science” (/tags/science) but there’s only a handful of items tagged with both “music” and “science” (/tags/music,science).
This being Huffduffer, where just about every page has corresponding JSON, RSS and Atom representations, you can also subscribe to the podcast of everything tagged with both “music” and “science” (/tags/music,science/rss).
There’s an OR operator as well; the vertical pipe symbol. You can view the 60 items tagged with “html5”, the 14 items tagged with “css3”, or the 66 items tagged with either “html5” or “css3” (/tags/html5|css3).
Wait a minute …66 items? But 60 plus 14 equals 74, not 66!
The discrepancy can be explained by the 8 items tagged with both “css3” and “html5” (/tags/html5,css3).
The AND and OR operators can be combined, so you can find items tagged with either “science” or “religion” that are also tagged with “politics” (/tags/science|religion,politics).
While it’s fun to do this in the browser’s address bar, I think the real power is in the way that the corresponding podcast allows you to subscribe to precisely-tailored content. Find just the right combination of tags, click on the RSS link, and you’re basically telling iTunes to automatically download audio whenever there’s something new that matches criteria like:
- everything that is tagged with either “science fiction” or “fantasy” or “horror” and is also tagged with “romance” (
/tags/science+fiction|fantasy|horror,romance), - everything that is tagged with “google” and is also tagged with either “apple” or “microsoft” or “yahoo” (
/tags/google,apple|microsoft|yahoo).
I’m sure there are plenty of intriguing combinations out there. Now I can use Huffduffer’s URLs to go spelunking for audio gems at the most promising intersections of tags.