/**
 * Represents a single command-line flag.
 */
export declare class Flag {
    readonly name: string;
    readonly description: string;
    readonly required: boolean;
    readonly type: FlagType;
    readonly default: string;
    private internalIsPresent;
    private internalValue;
    constructor(config: FlagConfig);
    /**
     * Returns true if this flag is present on this run. Will always return false
     * before flags are parsed with StrictFlags.parse().
     */
    isPresent(): boolean;
    /**
     * Returns the value of this flag, if this flag is a PROPERTY type and has
     * a value. Otherwise returns the default.
     * @throws Throws if this flag is not a PROPERTY.
     */
    get(): string;
    /**
     * Marks this flag as present. Should only be used in tests or by the actual
     * StrictFlags code. If this flag is PROPERTY type, a non-null value must be
     * supplied.
     * @throws Throws if this is a PROPERTY flag and no non-null value was
     *   provided. Also throws if this is a FLAG flag and any value is provided.
     */
    setPresence(value?: string | null): void;
    /**
     * Given a list of arguments, tries to locate this flag within them. If
     * successful, sets presence and value, or throws if something is amiss.
     * Removes itself from the list of arguments once complete.
     */
    parse(args: string[]): string[];
    /**
     * Returns the leading dashes that are used to form this entire flag.
     */
    getPrefix(): string;
    /**
     * Returns the full name of this flag, with the leading dashes.
     */
    getFullName(): string;
    private throwNoValueError;
    /**
     * Asserts the given config is valid by verifying the following conditions
     * are true:
     *
     *   - If this has the FLAG type, it does not also include a default.
     *
     *   - The flag name is not a reserved flag name.
     */
    private static assertConfigValid;
}
export interface FlagConfig {
    /**
     * The name of the flag, without the preceding dashes. Typically this is in
     * kebab-case, ie. "my-cool-flag".
     */
    name: string;
    /**
     * The description of the flag, used when a user runs "yourcli --help" or
     * "yourcli help <command>".
     */
    description: string;
    /**
     * Defaults to false. Whether or not to stop execution and alert if this flag
     * isn't present.
     */
    required?: boolean;
    /**
     * Defaults to FLAG. The type of this flag.
     */
    type?: FlagType;
    /**
     * Defaults to an empty string. The default value to fall back on if no value
     * is provided by the user.
     */
    default?: string;
    internalOnlyDoNotUseIsBuiltIn?: boolean;
}
export declare enum FlagType {
    FLAG = 0,
    PROPERTY = 1
}