/**
 * Lexicon Service
 *
 * Provides query expansion using domain-specific synonyms.
 * Part of Structured Semantic Expansion (SSE) for improved search recall.
 *
 * This is a pure domain service with no external dependencies.
 */
import type { Lexicon, Synonym, ExpandedQuery, ExpansionOptions } from "../entities/lexicon";
import { DEFAULT_EXPANSION_OPTIONS, EXPANSION_WEIGHTS } from "../entities/lexicon";
/**
 * Default lexicon for programming domain.
 *
 * Contains common synonyms for code-related terms.
 * Grades indicate correlation strength:
 * - strong: Near-equivalent (function ↔ method)
 * - moderate: Related but distinct (function ↔ handler)
 * - weak: Loosely associated (auth ↔ security)
 */
export declare const DEFAULT_LEXICON: Lexicon;
/**
 * Get synonyms for a term from the lexicon.
 *
 * @param term - The term to look up
 * @param lexicon - The lexicon to use (defaults to DEFAULT_LEXICON)
 * @returns Array of synonyms with grades, or empty array if not found
 */
export declare function getSynonyms(term: string, lexicon?: Lexicon): Synonym[];
/**
 * Expand a query using the lexicon.
 *
 * @param query - The original query string
 * @param lexicon - The lexicon to use (defaults to DEFAULT_LEXICON)
 * @param options - Expansion options
 * @returns Expanded query with weights
 */
export declare function expandQuery(query: string, lexicon?: Lexicon, options?: ExpansionOptions): ExpandedQuery;
/**
 * Get expansion weights by grade (re-exported for convenience).
 */
export { EXPANSION_WEIGHTS };
/**
 * Get default expansion options (re-exported for convenience).
 */
export { DEFAULT_EXPANSION_OPTIONS };