/**
 * jupytext percent-format adapter for #-comment languages (.py, .R, .jl).
 *
 * The format is defined entirely in terms of `#` line comments (markers,
 * header, commented markdown bodies), so the same parser/serializer works
 * verbatim for any language that uses `#` comments — Python, R, Julia.
 * The file extension only decides the default kernel (see registry).
 *
 * Format essentials:
 *   - optional jupytext-style header: `# ---` / `# `-prefixed YAML / `# ---`
 *   - `# %%` markers start cells; `[markdown]` / `[raw]` tag cell type;
 *     `id=<token>` carries the Nebula cell id (jupytext-legal key=value)
 *   - markdown/raw bodies are `# `-commented
 *   - outputs and execution counts are never serialized
 *
 * Anything on a marker line that we don't understand is preserved verbatim
 * (cell._metadata.percent_header_rest) and re-emitted — never interpreted.
 */
import { NotebookFormatAdapter } from './types';
/** Content-based discrimination (the VS Code/jupytext convention): a .py
 *  file IS a percent notebook iff it has a `# %%` cell marker or a jupytext
 *  header. Marker-less files are plain scripts — Nebula must never write
 *  metadata into them as a side effect of merely opening them. */
export declare function isPercentNotebookText(text: string): boolean;
export declare const percentAdapter: NotebookFormatAdapter;