/**
 * Every tag of the compute language, and the attributes each one reads.
 *
 * ONE list, with two readers: the evaluator reads an attribute only through
 * `attrOf`, whose type admits the names listed here and no other, and the
 * validator refuses any name that is not listed. A tag cannot learn to read an
 * attribute without this table knowing — the build fails first — so the
 * validator's idea of what a tag accepts cannot drift from what it reads.
 *
 * It exists because nothing checked these names at all. `<gen>` refuses an
 * attribute it does not have (TDC015); a compute tag took any name, and an
 * attribute it does not read changed the output without a word:
 *
 *     <join sep="-">        ->  a-b-c
 *     <join seperator="-">  ->  abc
 *
 * Measured by the Studio agent over sixteen attributes: nine misspellings
 * passed `check`, and eight of those produced a different file. The seven that
 * were refused were refused for the wrong reason — the value the attribute
 * carried had gone missing, and the complaint pointed at whatever needed it,
 * one tag further down.
 *
 * The keys are also the tag vocabulary: `COMPUTE_TAGS` is read off this table
 * rather than kept beside it.
 */
import type { AttrMap } from '../processor/attrs.js';
export declare const COMPUTE_ATTRIBUTES: {
    readonly int: readonly ["v"];
    readonly str: readonly ["v"];
    readonly list: readonly ["v"];
    readonly field: readonly ["name"];
    readonly use: readonly ["name"];
    readonly current: readonly [];
    readonly current_index: readonly [];
    readonly acc: readonly [];
    readonly let: readonly ["name"];
    readonly each: readonly [];
    readonly reduce: readonly [];
    readonly join: readonly ["sep"];
    readonly split: readonly ["sep"];
    readonly at: readonly ["default"];
    readonly length: readonly [];
    readonly add: readonly [];
    readonly subtract: readonly [];
    readonly multiply: readonly [];
    readonly divide: readonly [];
    readonly mod: readonly [];
    readonly encode: readonly ["as"];
    readonly to_number: readonly [];
    readonly pad: readonly ["width", "fill"];
    readonly concat: readonly [];
    readonly upper: readonly [];
    readonly lower: readonly [];
    readonly capitalize: readonly [];
    readonly title: readonly [];
    readonly mask: readonly ["pattern"];
    readonly slice: readonly ["from", "to"];
    readonly replace: readonly ["from", "to"];
    readonly trim: readonly [];
    readonly group: readonly ["size", "sep"];
    readonly choose: readonly [];
    readonly when: readonly [];
    readonly otherwise: readonly [];
    readonly test: readonly [];
    readonly then: readonly [];
    readonly result: readonly [];
    readonly over: readonly [];
    readonly do: readonly [];
    readonly init: readonly [];
    readonly in: readonly [];
    readonly index: readonly [];
    readonly equals: readonly [];
    readonly greater_than: readonly [];
    readonly less_than: readonly [];
    readonly is_digit: readonly [];
};
export type ComputeTag = keyof typeof COMPUTE_ATTRIBUTES;
/** The attributes `T` reads. */
export type ComputeAttr<T extends ComputeTag> = (typeof COMPUTE_ATTRIBUTES)[T][number];
/**
 * Accepted on every compute tag and read by none: a note for the reader, the
 * same as on every other tag. Refusing it on the one tag that happens not to
 * list it would be a pointless trap.
 */
export declare const ANY_COMPUTE_TAG_ATTRIBUTE = "comment";
/** The attributes a compute tag accepts, or `undefined` for a tag the language does not have. */
export declare function computeAttributesOf(tag: string): readonly string[] | undefined;
/**
 * Read attribute `name` of a `<tag>` node. `tag` is there for the type only:
 * it is what makes reading an unlisted attribute a compile error.
 */
export declare function attrOf<T extends ComputeTag>(attrs: AttrMap, _tag: T, name: ComputeAttr<T>): string | undefined;
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