import { Expression } from '../core/expression';
import { DataType } from '../types/data-type';
import { EvaluationContext } from '../types/evaluation-context';
export declare class LetExpression implements Expression {
    readonly input: Expression;
    readonly variableSymbol: symbol;
    readonly body: Expression;
    get dataType(): DataType;
    constructor(input: Expression, variableSymbol: symbol, body: Expression);
    evaluate(context: EvaluationContext): any;
}
export declare function letIn<TValue, TBody>(value: Expression<TValue>, body: (v: Expression<TValue>) => Expression<TBody>): Expression<TBody>;