import Ast from "./Ast";

export interface Context {
    [key: string]: any;
}

declare class Expression {
    constructor(lang: any, exprStr: string);

    /**
     * Forces a compilation of the expression string that this Expression object
     * was constructed with. This function can be called multiple times; useful
     * if the language elements of the associated Jexl instance change.
     * @returns this Expression instance, for convenience
     */
    compile(): Expression;

    /**
     * Asynchronously evaluates the expression within an optional context.
     * @param context A mapping of variables to values, which will be
     *      made accessible to the Jexl expression when evaluating it
     * @returns resolves with the result of the evaluation.
     */
    eval(context?: Context): Promise<any>;

    /**
     * Synchronously evaluates the expression within an optional context.
     * @param context A mapping of variables to values, which will be
     *      made accessible to the Jexl expression when evaluating it
     * @returns the result of the evaluation.
     * @throws on error
     */
    evalSync(context?: Context): any;

    /**
     * Get the abstract syntax tree that represents the compiled expression
     * @returns the abstract syntax tree
     */
    _getAst(): Ast;
}

export default Expression;