import { QueryNode } from './base.js';
/**
 * Gets the index the next VariableQueryNode will be assigned
 *
 * Variable indices are assigned in ascending order, so all variables created between two calls of this function have
 * an index in the range [first result, second result).
 */
export declare function peekNextVariableIndex(): number;
/**
 * A node that evaluates to the value of a variable.
 *
 * Use in a VariableAssignmentQueryNode or in a TransformListQueryNode to assign a value
 */
export declare class VariableQueryNode extends QueryNode {
    readonly label?: string | undefined;
    constructor(label?: string | undefined);
    readonly index: number;
    equals(other: this): boolean;
    toString(): string;
    describe(): string;
}
/**
 * A node that sets the value of a variable to the result of a node and evaluates to a second node
 *
 * LET $variableNode = $variableValueNode RETURN $resultNode
 *
 * (function() {
 *   let $variableNode = $variableValueNode
 *   return $resultNode
 * })()
 */
export declare class VariableAssignmentQueryNode extends QueryNode {
    constructor(params: {
        variableValueNode: QueryNode;
        resultNode: QueryNode;
        variableNode: VariableQueryNode;
    });
    static create(valueNode: QueryNode, resultNodeFn: (variableNode: QueryNode) => QueryNode, varLabel?: string): VariableAssignmentQueryNode;
    readonly variableValueNode: QueryNode;
    readonly resultNode: QueryNode;
    readonly variableNode: VariableQueryNode;
    describe(): string;
}
/**
 * A wrapper around an expression that should be hoisted out of certain contexts
 *
 * This is a simpler version of a variable assignment (which is also hoistable) but does not require
 * a variable. For this reason, it cannot be used if the expression is used multiple times.
 */
export declare class HoistableQueryNode extends QueryNode {
    readonly node: QueryNode;
    /**
     * The name of the variable this node would be assigned to when hoisted
     */
    readonly variableLabel: string;
    constructor(node: QueryNode, 
    /**
     * The name of the variable this node would be assigned to when hoisted
     */
    variableLabel: string);
    describe(): string;
}