/**
 * Builtin Function Registry
 *
 * Core-owned registration point for the builtin function table. The table
 * itself lives in `runtime/ext/builtins.ts`, which sits above core in the
 * layer order, so core cannot import it directly (enforced by the
 * `no-restricted-imports` layer rules in .oxlintrc.json). Instead, ext
 * registers its table here at module load, and core consumers
 * (`context.ts`, `introspection.ts`) read from this registry.
 *
 * Contract: the registered table is treated as frozen after registration.
 * Mutating it afterwards produces stale cache entries.
 */
import { type ApplicationCallable, type RillFunction } from './callable.js';
/**
 * Register the builtin function table. Called by `runtime/ext/builtins.ts`
 * at module load. `untypedNames` lists builtins that are genuinely variadic
 * and must skip arg validation.
 */
export declare function registerBuiltinFunctions(fns: Record<string, RillFunction>, untypedNames: ReadonlySet<string>): void;
/** Builtin functions as pre-parsed callables, keyed by name. */
export declare function getBuiltinFunctionCache(): ReadonlyMap<string, ApplicationCallable>;
/** True when `name` is a registered builtin function. */
export declare function isBuiltinFunctionName(name: string): boolean;