@wildwinter/scoperegistry

The scope registry / runtime state container that sits on top of @wildwinter/expr. expr is a stateless calculator; this package is the state layer.

It owns the world state as a set of named scopes, each either:

• owned — a property bag this registry stores, seeds from declaration defaults, and serializes via save/load; or
• foreign — host- or other-engine-resolved at runtime through a { get, set? } resolver, never stored here (read-only if there's no setter).

It then produces the two things expr consumes:

• toEvalContext() → the EvalContext for evaluate (owned bags + foreign resolvers).
• toSchema() → the ExpressionSchema for validateExpr (from declarations; undeclared scopes are opaque and unflagged).

Plus readScopeRegistrySpec(json) — extract a scopeRegistrySpec (the interop format) from any JSON value (a .storyworld bundle, or a standalone manifest), so one owner's scope declarations can be imported for validation by another engine.

expr never depends on this; this depends one-way on expr. Read-only is settable per scope (a resolver with no set) and per property (writable: false), enforced by set.

import { ScopeRegistry } from "@wildwinter/scoperegistry";

const reg = new ScopeRegistry()
  .defineOwned("patter", [{ name: "hp", type: "number", default: 10 }])
  .defineForeign("game", { get: (n) => host.read(n), set: (n, v) => host.write(n, v) });

evaluate(ast, reg.toEvalContext(), dialect);   // reads owned + foreign
validateExpr(ast, reg.toSchema(), dialect);    // checks declared scopes
const blob = reg.save();                        // owned scopes only

Design rationale: design/scope-registry.md in the Patter repo.