Tag rules reorganization

[Akamar]

The tagging mechanism is quite expressive, but its rule system isn't complete enough. Now we have rules only for entry links, titles, and content, but the same has feed itself (content is a description many feeds promote).

Feed link is equal for empty feed rule, descriptions aren't used by the app yet, so I suggest to add one new rule: feed-name (or feed-title). Here is example of using that rule (and why I need it for).

Let's suppose I have a list of feeds

• 004 | GNU Guix — Blog
• 070 | BBC World
• 004+51 | Project Euler

Codes before | are from Universal Decimal Classification (see the link), added manually and represent a thematic category of feed. I can create the following tags with rules:

• 004 IT&CS
  • feed-title contains "004"
• 070 Newspapers. The Press. Journalism
  • feed-title contains "070"
• 51 Mathematics
  • feed-title contains "51" or feed-title contains "+51"

And then I don't need to add 150 feeds of that categories manually. When I change my mind about BBC and add "070:3" code in the feed title, a tag "3 Society" will already show me the "news about society" from BBC. The maintaining of tags will be easy.

P.S. And, of course, regular expressions would be handy, though it lacks performance and simplicity.