import type { IndexProjectionDefinition, ProjectionDefinition } from './model-types.js';
export declare function isIndexProjection(projection: ProjectionDefinition): projection is IndexProjectionDefinition;
/**
 * Render an index expression list the way ClickHouse itself echoes it back:
 * a single element is bare (`INDEX b`), several are a tuple (`INDEX (a, b)`).
 *
 * Both halves matter. ClickHouse rewrites `INDEX (b)` to `INDEX b`, so without
 * this a pulled schema would drift against the live table forever; and it
 * rejects `INDEX a, b` outright, so multiple elements must be parenthesized.
 *
 * Must be idempotent: it runs at canonicalize time and again at render time,
 * and a canonical form that keeps changing makes every `generate` re-emit a
 * drop + rebuild of the projection.
 */
export declare function normalizeProjectionIndex(index: string): string;
export declare function canonicalizeProjection(projection: ProjectionDefinition): ProjectionDefinition;
export declare function renderProjectionBody(projection: ProjectionDefinition): string;
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