nx_css_selector_match.nx

nx_css_selector_match.nx -- match a parsed CssRule selector against an element's (tag, id, class-list). Phase 2 third primitive after nx_css_tokenize and nx_css_parse; the core of the eventual nx_css_apply layer that walks a DOM tree and cascades styles. Subset matched: TAG selector -- exact case-sensitive byte-equal vs element tag CLASS selector -- one of the whitespace-separated tokens in the element's class attribute byte-equal ID selector -- byte-equal vs the element's id attribute What it does NOT handle yet (named Phase 2b improvements): - case-insensitive tag matching for HTML mode (HTML5 lowercases tags; until nx_html_tokenizer normalizes, callers can pre-lowercase) - compound selectors (h1.foo) -- needs Phase 2b - descendant chains (header h1) -- needs DOM-tree context - sibling/child combinators (+ ~ >) - attribute selectors [href^="..."] - pseudo-classes (:hover, :nth-child) - namespace selectors Per cardinal feedback-honest-perf-verdict-no-aspirational-claims: gap list is EXACT and tested. genealogy_id: w3c_css_selectors_module_level_3 + substrate_browser_phase_2_selector_match lineage_id: nishi_browser_css_selector_match_v1 nx_safety_envelope: intended_use: "CSS selector match -- browser front-end style apply" sil_target: SIL1 evidence: [W3C_CSS_Selectors_canonical_basis, sealed_selector_kind_enum, bounded_class_list_walk, pure_function_no_allocation] verdict: NOT_YET_EVALUATED