Add alternatives to the rating system.

[Paradyx]

Rating songs on 1-5 stars has never been my go-to approach for rating music, due to it's absolute nature. I really like your tool, but I think it would benefit from some alternative rating systems:

1. like(255), neutral(0), dislike(1),
2. incremental likes, similar to mpdfav

The current 5-star rating and other rating systems do not need to exclude one another. The can live side-by-side in different stickers. Or perhaps those could be additional commands to mppopm: like, dislike, and reset that would increment/decrement the already existing rating value.

In additions, one could try to find heuristic for identifying most liked music.

I might implement this by myself, if you don't have the time. For now, I just wanted to share my idea with you, and the rest of the world :)

[sp1ff]

Thanks for filing this!
One minor point: the rating today is stored as an integer between 0 & 255, inclusive. The "one-to-five stars" system is just shorthand for that.
To your broader point: I can certainly see different users wanting to utilize their own ratings system, but I'd be reluctant to just ram whatever value the user gives to the set-rating command into the database. To extend your example: suppose I read the rating and get a value of "1". What does that mean? Is that 1 on a scale of 0-255, or "dislike" (to use your example)?
Perhaps we could write the rating as an some kind of URN; so instead of just an integer, it could be something like "com.github.paradyx:1" meaning 1/dislike in paradyx's rating system, whereas "com.github.sp1ff:1" would be one out of a possible 255?