Core structures and state

Core separates what exists from what the user is doing with it.

Structure	Answers
sequence	Which stable identities exist, and in what order?
range	Which quantized values are valid between bounds?
grid	Which identities occupy rows and columns?
tree	Which identities are parents, children, and visible descendants?

Cursor, selection, expansion, and text editing are independent state. A Listbox combines a sequence with cursor and selection. A Tree View adds a tree and expansion. The same selection rules can therefore be reused without copying a complete component machine.

import { createSequence } from '@sectile/core/sequence'
import { createRange } from '@sectile/core/range'

const tabs = createSequence(['overview', 'activity', 'settings'])
const volume = createRange({ origin: '0', step: '5', count: 20 })

Ownership boundary

Core structures own logical identity and validity. They do not own loaded records, pixel coordinates, labels, or DOM nodes. Use @sectile/core/collection-window for asynchronous loaded ranges and @sectile/virtual for rendered geometry.

The complete formal vocabulary remains available in Core theory.