dom

type Node struct {
	Type     NodeType
	Tag      string            // lowercased tag name (Element only)
	Attr     map[string]string // lowercased attribute names (Element only)
	Text     string            // character data (Text and Comment)
	Parent   *Node
	Children []*Node

	// Quirks is set on the Document (root) node when the source had no
	// `<!DOCTYPE ...>` at all — the single most common real-world trigger for
	// "quirks mode" (a page that never opted into standards mode). It is the
	// scoped case this engine detects; the HTML spec's fuller algorithm also
	// triggers quirks mode for specific legacy PUBLIC/SYSTEM doctype
	// identifiers (e.g. HTML 4.01 Transitional without a system ID), which
	// are vanishingly rare on real pages that reach this engine and are not
	// modelled — a page with ANY doctype is treated as standards mode here.
	// Confirmed load-bearing live: news.ycombinator.com ships no doctype at
	// all (`<html lang="en" op="news">` directly), and real browsers'
	// quirks-mode UA stylesheet resets `table{text-align:initial}` — without
	// which its `<center><table>...</table></center>` page shell (used only
	// to centre the table AS A BLOCK on the page) inherits centered text
	// into every cell, visibly wrong for cells the real page never intended
	// to centre (see css/ua.go's quirks-mode table rule).
	Quirks bool

	// Indeterminate is an <input type=checkbox>'s own "indeterminate" IDL
	// state (HTML Standard §4.10.5.1.19): unlike Checked, it has NO backing
	// content attribute at all — script is the only way to set it, so it
	// lives here as a plain runtime field, the same shape as Quirks/Shadow
	// above, rather than in Attr. Confirmed real usage: github.com's own
	// behaviors.js sets `checkbox.indeterminate = true` on page load for any
	// `[data-indeterminate]`-marked checkbox (its "select all" bulk-action
	// tri-state pattern). Backs the JS `.indeterminate` accessor and the
	// `:indeterminate` CSS pseudo-class (css/selector.go).
	Indeterminate bool

	// CustomValidity holds a form control's own "custom error message" set by
	// script via `.setCustomValidity(msg)` (HTML Standard's Constraint
	// Validation API) — empty means no custom error. This engine models NO
	// native constraints at all (no required/pattern/min/max/step checking
	// against a value), so this is the ONLY thing that can ever make
	// `.validity.valid`/`.checkValidity()` false — a deliberate, disclosed
	// scope boundary: this backs the real, evidenced usage (see js/dom.go's
	// own doc comment), not a full constraint-validation engine. Runtime-only
	// field, the same shape as Indeterminate above — there is no
	// "customvalidity" content attribute.
	CustomValidity string

	// Shadow is the shadow root attached to this element (a declarative
	// <template shadowrootmode> hoisted out at parse time — see
	// attachDeclarativeShadowRoots), or nil for a plain element. When set,
	// cascade and layout render Shadow.Children in place of this element's
	// own Children — the light-DOM Children above are NOT rendered directly;
	// they are visible only where a <slot> inside the shadow tree projects
	// them (see layout.renderedChildren / assignedSlotNodes).
	Shadow *ShadowRoot
	// ShadowHost is set on every node belonging to a shadow tree (recursively,
	// via markShadowHost) to that tree's host element; nil for an ordinary
	// light-DOM node. A <slot> element uses its own ShadowHost to find the
	// host whose light-DOM children it may project.
	ShadowHost *Node

	// Content is set on a <template> element (and only a <template> element)
	// to an inert "#fragment" node holding what would otherwise be its light-
	// DOM children — the HTMLTemplateElement.content DocumentFragment a real
	// browser exposes, per spec never rendered and never a template's own
	// Children. NewElement and convertChildren both set this up so every
	// <template>, however created, has one; SetInnerHTML/InnerHTML/serialize
	// all read and write through it instead of Children for this tag.
	// Real, confirmed live usage: lit-html's own template-cloning path reads
	// `templateEl.content` (see js.newTreeWalker's own doc comment, which
	// already documents `this.el.content` as the exact real expression
	// caniuse.com's lit-html-based web components read) — with no Content
	// field at all, `.content` was undefined, confirmed via a minimal
	// isolated repro to throw "Cannot read property 'cloneNode' of
	// undefined" the moment real cloning code touches it.
	Content *Node
	// contains filtered or unexported fields
}

type NodeType uint8

type ShadowRoot struct {
	// Host is the element this shadow root is attached to.
	Host *Node
	// Children are the shadow tree's top-level nodes (what a real
	// DocumentFragment's children would be) — the host's declarative
	// <template>'s .content, hoisted out of the light DOM. Their Parent
	// pointers are nil (they are the root of a separate tree); descendants
	// further down keep the ordinary Parent chain within the shadow tree.
	Children []*Node
}