/**
 * Plain-text Diagnostic Formatter
 *
 * Browser-safe (no ANSI colors). Produces human-readable error messages
 * with optional source context and caret indicators.
 *
 * @module
 */
import type { Diagnostic } from "./types.js";
/**
 * Format a single diagnostic as plain text.
 *
 * Without source: `[MEL_PARSER] Expected '{' (3:15)`
 * With source:
 * ```
 * [MEL_PARSER] Expected '{' (3:15)
 *    3 | domain Bad bad syntax here }
 *                ^^^
 * ```
 */
export declare function formatDiagnostic(diagnostic: Diagnostic, source?: string): string;
/**
 * Format multiple diagnostics, separated by blank lines.
 */
export declare function formatDiagnostics(diagnostics: Diagnostic[], source?: string): string;