export interface Fs {
    /**
     * An implementation should return a negative value if the first argument is
     * 'less' than the second, zero if they are 'equal', and a positive value if
     * the first argument is 'greater'.
     */
    compare(path1: string, path2: string): number;
    exists(path: string): boolean;
    isGlob(pattern: string): boolean;
    resolvePaths(pattern: string): string[];
}
export interface ValidatableRule {
    phony?: boolean;
    prereqs?: string[];
}
export interface ValidatableRules {
    [target: string]: ValidatableRule;
}
export interface ValidationResult {
    newerPrereqs: string[];
}
export interface ValidationResults {
    [invalidTarget: string]: ValidationResult;
}
export declare class Validator {
    private readonly fs;
    constructor(fs: Fs);
    validate(goal: string, rules: ValidatableRules): ValidationResults;
    private validateNonterminal;
    private validateTerminal;
    private resolve;
}