Trait StyledNode 

pub trait StyledNode {
    // Required methods
    fn type_name(&self) -> &str;
    fn id(&self) -> Option<&str>;
    fn classes(&self) -> Classes<'_>;
    fn state(&self) -> State;

    // Provided method
    fn position(&self) -> Position { ... }
}

The minimal contract the cascade needs to match selectors against an element.

Implement this on your framework’s node type (e.g. a2ui’s ComponentModel, or a plain app-state struct in a vanilla ratatui app).

For the draw-loop hot path prefer NodeRef (zero-allocation). OwnedNode remains available for convenience where owned String/Vec<String> storage is preferable.

Required Methods

fn type_name(&self) -> &str

Element type name — matches a CSS type selector (e.g. "Button").

fn id(&self) -> Option<&str>

Element id — matches a CSS #id selector.

fn classes(&self) -> Classes<'_>

Class names — match CSS .class selectors.

Returns a Classes<'_> borrow view rather than an allocating Vec<&str>. NodeRef makes this zero-allocation; OwnedNode pays one Vec allocation (it is not the hot path). The cascade hoists this call out of the per-rule loop so the cost is paid at most once per node regardless.

fn state(&self) -> State

Pseudo-class state — matches :focus / :disabled / etc.

Provided Methods

fn position(&self) -> Position

Sibling position — for future :nth-child support.

This is optional: :nth-child matching is P3 and not yet wired into the cascade, so compute does not consult it. The default returns an empty Position. Override it only when you need :nth-child data at some future point — until then, leaving the default avoids forcing every node type to materialize sibling info.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl StyledNode for OwnedNode

impl<'a> StyledNode for NodeRef<'a>