Selector-style derived state helpers (ecosystem-level).

This crate provides a small, explicit "derived state" primitive:

• memoize an expensive computation behind a dependency signature (Deps: PartialEq)
• keep the kernel (fret-ui) mechanism-only (ADR 0066)

A selector is intentionally not a global reactive graph. It is a local cache that can live in:

• element state (ElementContext::with_state_*) via the optional ui feature, or
• app/window state (e.g. inside a Model<T> payload)

Design constraints:

• no hidden ModelStore borrows across user code (user code runs outside of any store guard)
• dependency tracking is explicit: callers must provide a dependency signature

fret-selector

Derived state selector utilities for Fret apps and components.

A selector is a small, explicit derived-state primitive:

• memoize an expensive computation behind a dependency signature (Deps: PartialEq)
• keep dependency tracking explicit (no hidden global reactive graph)

Status

Experimental learning project (not production-ready).

Features

• ui: element-context helpers for collecting dependency tokens while registering observations