CSS Selector and Logical Operation

japanese Version(Qiita)

OR

A, B {}

AND

AB {}

NOT

:not(A) {}

NOR

:not(A, B) {} /* Currently undefined syntax  */

That way is so simply, but can't it now．
Selectors Level 4 which is under working draft, defined this syntax.

At such times De Morgan's law is convenient.

Since NOR is "NOT A" AND "NOT B", it can be written as follows.

:not(A):not(B) {}

If there are three or more selectors, the selector becomes dirty.　I hope to be implemented Selectors Level 4.

NAND

It's simpler then NOR．

:not(AB) {}

Adapting Domorgan's law in the same way as NOR, so

:not(A), :not(B) {}

is OK.

XOR

XOR is "A AND NOT B" OR "NOT A AND B", so it can be written as follows.

A:not(B), :not(A)B {}

(Maybe, A:not(B), B:not(A) is simpler.)

Impression

Actually, I was thinking about doing NOR things and started thinking about this at the trigger.

When doing something complicated, it seems to be easy to deal with remembering aggregate logic and doing this kind of things.