Plumeria 19.8

Plumeria v19.8 rewrites how the compiler reads selector keys. The algorithm was proposed by Anionix.

1. One pass for specificity

Specificity is computed in a single pass with a stack of frames, without recursion or copies of the selector. It is 3 to 9 times faster on short keys and about twice as fast on a 4 KB key. Valid selectors get the same specificity as in 19.7.

2. Fixes

A comment in a key no longer counts toward specificity, so '.a/* #b */' is not ordered as if it held an ID.
:nth-child(2n OF .a) reads OF in any case, as CSS keywords are case-insensitive.
A stray or unclosed quote, such as ':hover":is(.x)', stops the build.

3. Selector rules

:not() can nest inside :not() again. Unlike :is() or :where(), a :not() inside :not() changes what the selector matches, so it cannot be flattened:

':not(:not(.a), .b)' // matches .a, but not .b
':not(.a, .b)'       // matches neither

A key can nest :not() and functional pseudo-classes of different names up to 16 levels deep. Any other functional pseudo-class still cannot nest inside one of the same name, as in 19.7:

':is(:where(.a))'      // allowed
':is(:where(:is(.a)))' // stops the build

no-invalid-selector reports the same keys the compiler rejects. Neither a person nor an AI agent can write a key past these limits: the lint reports it, and the compiler stops the build. See selector rules.