/**
 * Dvala source formatter — CST-based.
 *
 * Parses source into a concrete syntax tree (CST) that preserves all tokens
 * including comments and whitespace, then formats it using a Wadler-Lindig
 * document algebra. Comments are preserved at their logical positions.
 * Structural whitespace is normalized to canonical form.
 *
 * On parse failure the original source is returned unchanged so format-on-save
 * never destroys partially-written code.
 */
export declare function format(source: string): string;