import { Replace } from "@glas/traverse";
export declare enum ExpressionKind {
    Unknown = 0,
    Boolean = 1,
    Integer = 2,
    Float = 3,
    String = 4
}
export declare abstract class Expression {
    /**
     * This field can be used by client applications to store and later retrieve information.
     */
    source: unknown;
    kind: ExpressionKind;
    constructor(source?: unknown);
    /**
     * Returns true if this expression has no sub expressions.
     */
    get isTerminal(): boolean;
    /**
     * Returns true if this expressions child sub expressions are terminal.
     */
    get isShallow(): boolean;
    abstract readonly sortOrder: number;
    protected abstract toStringInternal(): string;
    compareSortOrderSameType(b: any): number;
    compare(b: Expression): number;
    isLessThan(b: Expression): boolean | null;
    splitExpressions(operator?: string): Iterable<Expression>;
    split(operator: string): Expression[];
    filter(filterFunction: (e: Expression) => Expression | Replace<Expression>): Expression;
    replace(find: Expression, replace: Expression): Expression;
    toString(): string;
    private static expressionToString;
}