User-defined "auto-tags"

[mwatts15]

Sometimes users will want to have tags automatically assigned, but not want to write their own add-on just for the functionality. Instead, they could be allowed to define tags in terms of simple expressions combining other tags.

For instance, say a user had an add-on tag rating that gave ratings culled from MusicBrainz for some of her MP3s. If she wanted to look at all of her highly rated MP3s she might go to filetype::mp3/rating:>4. If she wanted to use this combination frequently, it would be easier to give it a name like fav-mp3s.

This feature could be implemented as an add-on as well.

See also,

• Add-ons: Issue Add-On system for dynamic tag creation #5
• Extended tag specifiers: Issue Fix tspec query to work with other specifiers #2

(Note: Something like shell aliases work well for the command line, but aren't portable and don't solve this issue)