/**
 * Shared, dependency-free core for round-trip AST validation.
 *
 * This module is intentionally self-contained — it imports no parser or
 * deparser — so it can be lifted verbatim into an upstream package (e.g.
 * `@pgsql/round-trip`) and shared between:
 *
 *  - pgsql-parser's test fixtures (`cleanTree` / `expectParseDeparse`), which
 *    parse → deparse → re-parse and assert the normalized ASTs are equal, and
 *  - downstream mutation-aware validators (this package's
 *    round-trip check), which compare a *mutated* AST against the AST obtained
 *    by re-parsing the deparsed output.
 *
 * The upstream `cleanTree` is expressed here as a preset over the generic
 * `normalizeTree` engine; the downstream fortified normalizer layers extra
 * volatile keys, lazy-datum filtering, and body-sentinel handling on top of
 * the same engine (see round-trip.ts).
 */
export interface NormalizeTreeOptions {
    /** Object keys dropped entirely (volatile / non-semantic fields). */
    volatileKeys?: ReadonlySet<string>;
    /** Sort object keys so comparison is insensitive to key order. Default false. */
    sortKeys?: boolean;
    /** Array items for which this returns true are removed before recursing. */
    dropArrayItem?: (item: unknown) => boolean;
    /**
     * Per-key transform hooks keyed by object-property name. The hook receives
     * the value at that key plus a `recurse` callback (which re-enters
     * `normalizeTree` with the same options) and returns the replacement value.
     */
    keyHandlers?: Record<string, (value: any, recurse: (node: any) => any) => any>;
}
/**
 * Deep-clone an AST while dropping volatile keys, optionally sorting keys,
 * filtering array items, and applying per-key transform hooks. Primitives are
 * returned as-is; Dates are cloned (parity with the original upstream
 * `transform` helper).
 */
export declare function normalizeTree(node: any, options?: NormalizeTreeOptions): any;
/**
 * Return the JSON path of the first structural difference between two trees,
 * or null if they are deeply equal. Useful for actionable mismatch messages.
 */
export declare function firstDifference(a: any, b: any, path?: string): string | null;
/** Position/length fields stripped by the upstream `cleanTree`. */
export declare const CLEAN_TREE_VOLATILE_KEYS: ReadonlySet<string>;
/**
 * Trim the function/DO body string carried by a `DefElem` with defname "as".
 * Mirrors the in-place trimming in pgsql-parser's `cleanTree` so the body
 * text (whose surrounding whitespace legitimately shifts on deparse) does not
 * cause spurious AST mismatches. Mutates the passed DefElem in place.
 */
export declare function trimDefElemBody(defElem: any): void;
/**
 * Upstream-compatible normalization: strips `stmt_len` / `stmt_location` /
 * `location` and trims `DefElem` "as" body strings. Equivalent to
 * pgsql-parser's deparser `cleanTree`, provided here so upstream can adopt the
 * shared core without behavior change.
 */
export declare function cleanTree(tree: any): any;