/**
 * `weight="column"` — take the proportions from the FILE instead of the config.
 *
 * Without it a list is drawn uniformly, so `Smith` and `Zabrowski` appear
 * equally often. Real distributions are never flat: the top US surnames cover a
 * large share of the population while the tail is vanishingly rare, and a
 * dataset that flattens that is the first thing an analyst notices.
 *
 * The proportions are honoured EXACTLY, not on average — the same Hamilton
 * machinery `percent=` uses. Weights `20000` and `10000` over 30 000 rows give
 * precisely 20 000 and 10 000, not "about twice as many".
 *
 * A weight is a raw COUNT, not a percentage: census and SSA files publish
 * occurrence counts, and asking a user to normalise them by hand would be a
 * pointless invitation to arithmetic errors.
 * Spec: docs/specs/2026-07-19-en-us-pack-structure.md
 */
import type { FileSourceOptions } from './file.js';
export declare class WeightedFileError extends Error {
    readonly name = "WeightedFileError";
}
export interface WeightedValues {
    readonly values: string[];
    /** Share of the total, in percent — what the Hamilton path expects. */
    readonly percents: number[];
}
/** The `weight` attribute, or undefined when the column is not weighted. */
export declare function weightColumnOf(attrs: Record<string, string | undefined>): string | undefined;
/**
 * Read value and weight columns side by side and turn the counts into percents.
 *
 * Rows whose weight is zero are DROPPED rather than kept at zero probability:
 * a value that can never appear only costs the distribution machinery memory,
 * and census files carry plenty of them.
 */
export declare function loadWeightedValues(path: string, options: FileSourceOptions, weightColumn: string): WeightedValues;
/**
 * A weighted data-list pack as {values, percents}, or undefined when the pack
 * is absent or unweighted.
 *
 * Shared by BOTH engines so a weighted pack is drawn identically to a weighted
 * `text` or `file=` — the in-memory builder hands it to `distributeByPercent`,
 * the streaming builder into its slot machinery. Kept here, next to the other
 * weighted sources, so neither engine grows its own copy of the shape.
 */
export declare function weightedPackValues(entry: {
    values?: readonly string[] | undefined;
    percents?: readonly number[] | undefined;
} | undefined): {
    values: string[];
    percents: number[];
} | undefined;
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