import { CommandSegment, ArgumentSegment, NullSegment } from './command-registry';
interface StackObserver {
    update: () => void;
}
/**
 * A stack used to store command segments as they are (or were) entered by a user.
 */
export declare class SegmentStack {
    private segments;
    readonly nullSegment: NullSegment;
    private observers;
    subscribe(observer: StackObserver): void;
    unsubscribe(observer: StackObserver): void;
    private notifyObservers;
    /**
     * Clears all segments from the stack
     */
    clear(): void;
    /**
     * Pushes a new segment onto the stack
     */
    push(segment: CommandSegment): void;
    /**
     * Pushes an array of segments onto the stack
     */
    pushAll(segments: CommandSegment[]): void;
    /**
     * Removes and returns the top segment from the stack
     * Returns NullSegment if stack is empty
     */
    pop(): CommandSegment;
    /**
     * Returns the top segment without removing it
     * Returns NullSegment if stack is empty
     */
    peek(): CommandSegment;
    /**
     * Returns the number of segments in the stack
     */
    size(): number;
    /**
     * Returns true if the stack has no segments
     */
    isEmpty(): boolean;
    /**
     * Returns true if any segment in the stack is an argument
     */
    get hasArguments(): boolean;
    /**
     * Returns all argument segments in the stack
     */
    get arguments(): ArgumentSegment[];
    /**
     * Returns the command path as an array of segment names
     */
    path(): string[];
    /**
     * Returns a copy of the internal segments array
     */
    toArray(): CommandSegment[];
}
export {};