/**
 * A zero-dependency parser for the single file Lynx XML markup format.
 *
 * It is written without `DOMParser` or any third party XML library so that it
 * can run inside a Web Worker.
 *
 * The grammar accepted here is intentionally tiny:
 *
 * ```xml
 * <!doctype lynx>
 * <lynx engine-version="4.2">
 * <style> ... </style>
 * <script thread="main"> ... </script>
 * <script thread="background"> ... </script>
 * </lynx>
 * ```
 */
/**
 * The structured error describing why a document could not be parsed.
 */
export interface LynxXMLParseError {
    /**
     * The offset inside the source where the failure was detected, counted in
     * JavaScript string indices, i.e. UTF-16 code units. Note that the reference
     * implementation counts UTF-8 bytes instead, so for documents containing
     * non-ASCII text before the failure the two numbers differ.
     */
    offset: number;
    /**
     * The human readable reason, without the offset prefix.
     */
    message: string;
    /**
     * The full message, formatted exactly like the reference implementation:
     * `invalid TemplateBundle XML at offset <offset>: <message>`.
     */
    formattedMessage: string;
}
/**
 * The result of a successful parse.
 */
export interface LynxXMLParseSuccess {
    success: true;
    /**
     * The content of the `<style>` section. `undefined` when the document has no
     * `<style>` section, which is legal.
     */
    style: string | undefined;
    /**
     * The content of the `<script thread="main">` section. Always present, a
     * document without it is rejected.
     */
    mainThreadScript: string;
    /**
     * The content of the `<script thread="background">` section. `undefined`
     * when the document has no background script section, which is legal.
     */
    backgroundThreadScript: string | undefined;
}
/**
 * The result of a failed parse.
 */
export interface LynxXMLParseFailure {
    success: false;
    error: LynxXMLParseError;
}
/**
 * The discriminated union returned by {@link parseLynxXML}. Errors are returned
 * instead of thrown so that callers can forward them as `error` events.
 */
export type LynxXMLParseResult = LynxXMLParseSuccess | LynxXMLParseFailure;
/**
 * Parses a single file Lynx XML markup document into its three source sections.
 *
 * This never throws for malformed input: inspect the `success` discriminant of
 * the returned {@link LynxXMLParseResult} instead.
 *
 * @param source - The whole XML document. A leading UTF-8 BOM is tolerated.
 */
export declare function parseLynxXML(source: string): LynxXMLParseResult;