import type { DummyAppendMemoryMap, StatisticAppendProvider } from './file-provider';
/**
 * Requires source information to be attached on parsing!
 * <p>
 * Returns the content of the node (i.e., the text content excluding the children)
 */
export declare function extractNodeContent(node: Node): string;
/** by default, we do not write to anything */
export declare let statisticsFileProvider: StatisticAppendProvider;
/**
 * Make the statistics write to a given output directory.
 */
export declare function initFileProvider(outputDirectory: string): void;
/**
 * Either ignore the statistics or write them to a given map (e.g., for testing).
 *
 * @param map - The map to write to, will not persist calls if no map is given
 */
export declare function initDummyFileProvider(map?: DummyAppendMemoryMap): void;
/**
 * Format used to dump each entry of a feature during collection.
 */
export type StatisticsOutputFormat<T = string> = [
    /** the collected value (like the assignment operator lexeme, ...) */
    value: T,
    /** the context of the information retrieval (e.g. the name of the file that contained the R source code) */
    context: string | undefined
];
/**
 * Append the content of all nodes to the storage file for the given feature
 * @param name    - The name of the feature {@link Feature#name}
 * @param fn      - The name of the feature-aspect to record
 * @param nodes   - The nodes to append, you may pass already transformed string contents
 * @param context - The context of the information retrieval (e.g. the name of the file that contained the R source code)
 * @param unique  - Should duplicate entries be removed on addition
 */
export declare function appendStatisticsFile<T>(name: string, fn: keyof T, nodes: string[] | Node[] | object[], context: string | undefined, unique?: boolean): void;