import type { PostextConfig } from '../types.js';
/**
 * A book's configuration in layers (#1209): the general settings every
 * edition reads, and per language an override that changes only the fields
 * it names. The override is merged over the general settings field by
 * field:
 *
 * - objects merge key by key, down to the leaves;
 * - a colour (`hex`) or a length (`value` + `unit`) is one value, replaced
 *   whole;
 * - a list whose entries carry an `id` (`calloutStyles`, `headingStyles`,
 *   `colorPalette`, `resourceTypes`, a template's frames…) merges entry by
 *   entry on the `id`; a `levels` list (headings, lists, the contents)
 *   merges on `level`, `customFonts` on `name`. An entry the general list
 *   lacks is added after its entries; `{ id, $remove: true }` takes one
 *   out for this language (a list reordered in one language takes every
 *   general entry out, then lists its own);
 * - any other list (a fallback face stack, tab stops) is replaced whole;
 * - `null` takes a general value out: the field reads the language's
 *   default, as if neither layer set it.
 */
export type ConfigOverride = {
    [key: string]: unknown;
};
/** The marker an override list entry carries to take the general list's
 *  entry with the same key out. */
export declare const REMOVE_ENTRY = "$remove";
/** The configuration an edition lays out with: `override` over
 *  `general`, field by field (see {@link ConfigOverride}). Neither input
 *  is mutated; with no override, `general` itself. */
export declare function mergeConfigLayers(general: PostextConfig, override: ConfigOverride | undefined | null): PostextConfig;
/** The override that turns `general` into `own`: the fields `own` sets
 *  differently, `null` for the ones it leaves out, so that
 *  `mergeConfigLayers(general, diffConfigLayers(general, own))` is `own`
 *  (as JSON, key order aside). Empty when the two agree. */
export declare function diffConfigLayers(general: PostextConfig, own: PostextConfig): ConfigOverride;
/** Whether the two configurations say the same, key order aside. */
export declare function sameConfig(a: unknown, b: unknown): boolean;
/** The settings two or more editions agree on: the fields every one of
 *  `configs` sets to the same value, objects compared field by field and
 *  keyed lists entry by entry (an entry they all have, with the fields
 *  they agree on). What a book whose editions each kept a whole
 *  configuration shares, as its general settings. */
export declare function commonConfig(configs: readonly PostextConfig[]): PostextConfig;
/** Where `override` sets something: each leaf as a dotted path, list
 *  entries named by their key (`calloutStyles[id=note].background`,
 *  `headings.levels[level=2].fontSize`); a `null` (back to the default)
 *  and a removed entry are leaves too. */
export declare function overridePaths(override: ConfigOverride | undefined | null): string[];
/** The override that turns `general` into `own` with nothing a reader
 *  would not miss: a `null` (or a removed list entry) that `normalize`
 *  makes no difference for — the general value is the default of `own`'s
 *  language too, which normalizing `own` (stripping its defaults) took
 *  out — is left out. `own` is taken as `normalize` gives it. */
export declare function leastConfigOverride(general: PostextConfig, own: PostextConfig, normalize: (c: PostextConfig) => PostextConfig): ConfigOverride;
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