Boolean "not" operator in queries

[kript]

I'd like to be able to do reverse matching regex in beets so I can create smart playlists with one or more specific exclusions, i.e.;

beet list ^(?!undesirable)$

or

smartplaylist:
playlists:
- name: notaudiobooks.m3u
query: 'genre:^(?!(audiobook)|(spoken))$'

[sampsyo]

Sorry, I didn't quite make this clear over twitter: you can probably use regexes to do negation today using that syntax. Have you tried something like

beet list genre::^(?!audiobook)$

or something similar? (Note the double colon to enable regex search.)

What we should add is explicit support for the "not" operator in queries so that silly regex hacks like this are not necessary.

[kript]

Ah; I couldn't get that to work, I swear, but this now does;

beet ls genre::^'(?!kids)'

so, hurrah! and thank you, but having the not operator would be even nicer. :-)

[Profpatsch]

Syntax ideas:

Example: I want to find all album by artist Evanescence, but not their album “Evanescence”:

beet list "artist:evanescence -album:evanescence"

or maybe

beet list "artist:evanescence not album:evanescence"

[sampsyo]

Added in #1728.