import * as L from './lang.js';
import { Result } from './result.js';
export declare class ProgramState {
    env: L.Env;
    prog: L.Program;
    constructor(prog: L.Program, env?: L.Env);
    isFullyEvaluated(): boolean;
    step(): Promise<ProgramState>;
    evaluate(): Promise<ProgramState>;
    stepExp(e: L.Exp): Promise<Result<L.Value>>;
    evaluateExp(e: L.Exp): Promise<Result<L.Value>>;
    toString(outputBindings?: boolean): string;
}
export declare class ProgramTrace {
    states: ProgramState[];
    pos: number;
    constructor(initial: ProgramState);
    getCurrentState(): ProgramState;
    stepForward(): Promise<void>;
    stepBackward(): void;
    evalNextStmt(): Promise<void>;
    revertPrevStmt(): void;
    evaluateProg(): Promise<void>;
    resetProg(): void;
    currentStep(): number;
    currentState(): ProgramState;
    addStmt(src: string): Promise<void>;
}
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