/**
 * @file 块级语法拓展：YAML Frontmatter
 * @module transformer/extends/block/frontmatter
 *
 * 语法示例：
 * ```
 * ---
 * title: Hello
 * ---
 * ```
 *
 * 解析结果写入 store.frontMatter，并生成 invisible AST 节点供增量合并。
 */
import { BaseBlockParser } from "../../../transformer/core/ParserBase.js";
import type { BlockParseContext } from "../../../transformer/core/context/BlockParseContext";
/** 判断是否为 frontmatter 围栏行。 */
export declare function isFrontmatterFenceLine(line: string): boolean;
/** 文档含 frontmatter 时返回其结束行（0-based 不含），否则 0。 */
export declare function frontmatterEndLine(lines: string[]): number;
declare class FrontmatterBlockParser extends BaseBlockParser {
    constructor();
    canOpenAt(lines: string[], index: number, _ctx: BlockParseContext): boolean;
    parse(lines: string[], index: number, ctx: BlockParseContext): {
        nextIndex: number;
        node: import("../../../transformer/core/MarkdownNode.js").MarkdownNode;
    } | null;
    render(): string;
}
declare const _default: FrontmatterBlockParser;
export default _default;
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