Module builder

Helper module to build up a selector safely and efficiently.

Our selector representation is designed to optimize matching, and has several requirements:

• All simple selectors and combinators are stored inline in the same buffer as Component instances.
• We store the top-level compound selectors from right to left, i.e. in matching order.
• We store the simple selectors for each combinator from left to right, so that we match the cheaper simple selectors first.

For example, the selector:

.bar:hover > .baz:nth-child(2) + .qux

Gets stored as:

[.qux, + , .baz, :nth-child(2), > , .bar, :hover]

Meeting all these constraints without extra memmove traffic during parsing is non-trivial. This module encapsulates those details and presents an easy-to-use API for the parser.

Structs

ExactChain 🔒

SelectorBuilder

Top-level SelectorBuilder struct. This should be stack-allocated by the consumer and never moved (because it contains a lot of inline data that would be slow to memmove).

SelectorFlags 🔒

Flags that indicate at which point of parsing a selector are we.

Specificity 🔒

SpecificityAndFlags

Constants

MAX_10BIT 🔒

Functions

complex_selector_specificity_and_flags 🔒

relative_selector_list_specificity_and_flags 🔒

selector_list_specificity_and_flags 🔒

Finds the maximum specificity of elements in the list and returns it.

specificity_and_flags 🔒