import { ArrayIterator, IArrayLike, IIterable } from './iteration';
/**
 * A finite-length sequence of indexable values.
 */
export interface ISequence<T> extends IIterable<T> {
    /**
     * The length of the sequence.
     *
     * #### Notes
     * This is a read-only property.
     */
    length: number;
    /**
     * Get the value at the specified index.
     *
     * @param index - The positive integer index of interest.
     *
     * @returns The value at the specified index.
     *
     * #### Undefined Behavior
     * An `index` which is non-integral or out of range.
     */
    at(index: number): T;
}
/**
 * A sequence which allows mutation of the underlying values.
 */
export interface IMutableSequence<T> extends ISequence<T> {
    /**
     * Set the value at the specified index.
     *
     * @param index - The positive integer index of interest.
     *
     * @param value - The value to set at the specified index.
     *
     * #### Undefined Behavior
     * An `index` which is non-integral or out of range.
     */
    set(index: number, value: T): void;
}
/**
 * A type alias for a sequence or builtin array-like object.
 *
 * #### Notes
 * The [[seq]] function can be used to produce an [[ISequence]] for
 * objects of this type. This allows sequence algorithms to operate
 * on these objects in a uniform fashion.
 */
export declare type SequenceOrArrayLike<T> = ISequence<T> | IArrayLike<T>;
/**
 * A type alias for a mutable sequence or builtin array-like object.
 *
 * #### Notes
 * The [[mseq]] function can be used to produce an [[IMutableSequence]]
 * for objects of this type. This allows sequence algorithms to operate
 * on these objects in a uniform fashion.
 */
export declare type MutableSequenceOrArrayLike<T> = IMutableSequence<T> | IArrayLike<T>;
/**
 * Cast a sequence or array-like object to a sequence.
 *
 * @param object - The sequence or array-like object of interest.
 *
 * @returns A sequence for the given object.
 *
 * #### Notes
 * This function allows sequence algorithms to operate on user-defined
 * sequence types and builtin array-like objects in a uniform fashion.
 */
export declare function asSequence<T>(object: SequenceOrArrayLike<T>): ISequence<T>;
/**
 * Cast a mutable sequence or array-like object to a mutable sequence.
 *
 * @param object - The sequence or array-like object of interest.
 *
 * @returns A mutable sequence for the given object.
 *
 * #### Notes
 * This function allows sequence algorithms to operate on user-defined
 * sequence types and builtin array-like objects in a uniform fashion.
 */
export declare function asMutableSequence<T>(object: MutableSequenceOrArrayLike<T>): IMutableSequence<T>;
/**
 * A sequence for an array-like object.
 *
 * #### Notes
 * This sequence can be used for any builtin JS array-like object.
 */
export declare class ArraySequence<T> implements ISequence<T> {
    /**
     * Construct a new array sequence.
     *
     * @param source - The array-like object of interest.
     */
    constructor(source: IArrayLike<T>);
    /**
     * The length of the sequence.
     *
     * #### Notes
     * This is a read-only property.
     */
    readonly length: number;
    /**
     * Create an iterator over the object's values.
     *
     * @returns A new iterator which traverses the object's values.
     */
    iter(): ArrayIterator<T>;
    /**
     * Get the value at the specified index.
     *
     * @param index - The positive integer index of interest.
     *
     * @returns The value at the specified index.
     *
     * #### Undefined Behavior
     * An `index` which is non-integral or out of range.
     */
    at(index: number): T;
    protected _source: IArrayLike<T>;
}
/**
 * A sequence for a mutable array-like object.
 *
 * #### Notes
 * This sequence can be used for any builtin JS array-like object.
 */
export declare class MutableArraySequence<T> extends ArraySequence<T> implements IMutableSequence<T> {
    /**
     * Set the value at the specified index.
     *
     * @param index - The positive integer index of interest.
     *
     * @param value - The value to set at the specified index.
     *
     * #### Undefined Behavior
     * An `index` which is non-integral or out of range.
     */
    set(index: number, value: T): void;
}