import { ExprString } from '../expressions/expr-string';
import { Boolean } from '../expressions/boolean';
import { LiteralDay, LiteralHour, LiteralMonth, LiteralTimestamp, LiteralYear } from '../expressions/time-literal';
import { ExprNumber } from '../expressions/expr-number';
import type { ExpressionDef } from './expression-def';
export type Literal = LiteralTimestamp | LiteralHour | LiteralMonth | LiteralDay | LiteralYear | ExprNumber | ExprString | Boolean;
export declare function isLiteral(value: ExpressionDef): value is ExprString | ExprNumber | Boolean | LiteralTimestamp | LiteralHour | LiteralDay | LiteralMonth | LiteralYear;