/**
 * Multi-way trees (aka rose trees) and forests, where a forest is
 *
 * ```ts
 * type Forest<A> = Array<Tree<A>>
 * ```
 *
 * @since 2.0.0
 */
import { Applicative1 } from './Applicative'
import { Comonad1 } from './Comonad'
import { Eq } from './Eq'
import { Foldable1 } from './Foldable'
import { Functor1 } from './Functor'
import { HKT, Kind, Kind2, Kind3, URIS, URIS2, URIS3 } from './HKT'
import { Monad as MonadHKT, Monad1, Monad2, Monad2C, Monad3, Monad3C } from './Monad'
import { Monoid } from './Monoid'
import { Show } from './Show'
import { PipeableTraverse1, Traversable1 } from './Traversable'
/**
 * @category model
 * @since 2.0.0
 */
export declare type Forest<A> = Array<Tree<A>>
/**
 * @category model
 * @since 2.0.0
 */
export interface Tree<A> {
  readonly value: A
  readonly forest: Forest<A>
}
/**
 * @category constructors
 * @since 2.0.0
 */
export declare function make<A>(value: A, forest?: Forest<A>): Tree<A>
/**
 * @category instances
 * @since 2.0.0
 */
export declare function getShow<A>(S: Show<A>): Show<Tree<A>>
/**
 * @category instances
 * @since 2.0.0
 */
export declare function getEq<A>(E: Eq<A>): Eq<Tree<A>>
/**
 * Neat 2-dimensional drawing of a forest
 *
 * @since 2.0.0
 */
export declare function drawForest(forest: Forest<string>): string
/**
 * Neat 2-dimensional drawing of a tree
 *
 * @example
 * import { make, drawTree, tree } from 'fp-ts/Tree'
 *
 * const fa = make('a', [
 *   tree.of('b'),
 *   tree.of('c'),
 *   make('d', [tree.of('e'), tree.of('f')])
 * ])
 *
 * assert.strictEqual(drawTree(fa), `a
 * ├─ b
 * ├─ c
 * └─ d
 *    ├─ e
 *    └─ f`)
 *
 *
 * @since 2.0.0
 */
export declare function drawTree(tree: Tree<string>): string
/**
 * Build a tree from a seed value
 *
 * @category constructors
 * @since 2.0.0
 */
export declare function unfoldTree<A, B>(b: B, f: (b: B) => [A, Array<B>]): Tree<A>
/**
 * Build a tree from a seed value
 *
 * @category constructors
 * @since 2.0.0
 */
export declare function unfoldForest<A, B>(bs: Array<B>, f: (b: B) => [A, Array<B>]): Forest<A>
/**
 * Monadic tree builder, in depth-first order
 *
 * @category constructors
 * @since 2.0.0
 */
export declare function unfoldTreeM<M extends URIS3>(
  M: Monad3<M>
): <R, E, A, B>(b: B, f: (b: B) => Kind3<M, R, E, [A, Array<B>]>) => Kind3<M, R, E, Tree<A>>
export declare function unfoldTreeM<M extends URIS3, E>(
  M: Monad3C<M, E>
): <R, A, B>(b: B, f: (b: B) => Kind3<M, R, E, [A, Array<B>]>) => Kind3<M, R, E, Tree<A>>
export declare function unfoldTreeM<M extends URIS2>(
  M: Monad2<M>
): <E, A, B>(b: B, f: (b: B) => Kind2<M, E, [A, Array<B>]>) => Kind2<M, E, Tree<A>>
export declare function unfoldTreeM<M extends URIS2, E>(
  M: Monad2C<M, E>
): <A, B>(b: B, f: (b: B) => Kind2<M, E, [A, Array<B>]>) => Kind2<M, E, Tree<A>>
export declare function unfoldTreeM<M extends URIS>(
  M: Monad1<M>
): <A, B>(b: B, f: (b: B) => Kind<M, [A, Array<B>]>) => Kind<M, Tree<A>>
export declare function unfoldTreeM<M>(
  M: MonadHKT<M>
): <A, B>(b: B, f: (b: B) => HKT<M, [A, Array<B>]>) => HKT<M, Tree<A>>
/**
 * Monadic forest builder, in depth-first order
 *
 * @category constructors
 * @since 2.0.0
 */
export declare function unfoldForestM<M extends URIS3>(
  M: Monad3<M>
): <R, E, A, B>(bs: Array<B>, f: (b: B) => Kind3<M, R, E, [A, Array<B>]>) => Kind3<M, R, E, Forest<A>>
export declare function unfoldForestM<M extends URIS3, E>(
  M: Monad3C<M, E>
): <R, A, B>(bs: Array<B>, f: (b: B) => Kind3<M, R, E, [A, Array<B>]>) => Kind3<M, R, E, Forest<A>>
export declare function unfoldForestM<M extends URIS2>(
  M: Monad2<M>
): <R, E, B>(bs: Array<B>, f: (b: B) => Kind2<M, R, [E, Array<B>]>) => Kind2<M, R, Forest<E>>
export declare function unfoldForestM<M extends URIS2, E>(
  M: Monad2C<M, E>
): <A, B>(bs: Array<B>, f: (b: B) => Kind2<M, E, [A, Array<B>]>) => Kind2<M, E, Forest<A>>
export declare function unfoldForestM<M extends URIS>(
  M: Monad1<M>
): <A, B>(bs: Array<B>, f: (b: B) => Kind<M, [A, Array<B>]>) => Kind<M, Forest<A>>
export declare function unfoldForestM<M>(
  M: MonadHKT<M>
): <A, B>(bs: Array<B>, f: (b: B) => HKT<M, [A, Array<B>]>) => HKT<M, Forest<A>>
/**
 * @since 2.0.0
 */
export declare function elem<A>(E: Eq<A>): (a: A, fa: Tree<A>) => boolean
/**
 * Fold a tree into a "summary" value in depth-first order.
 *
 * For each node in the tree, apply `f` to the `value` and the result of applying `f` to each `forest`.
 *
 * This is also known as the catamorphism on trees.
 *
 * @example
 * import { fold, make } from 'fp-ts/Tree'
 *
 * const t = make(1, [make(2), make(3)])
 *
 * const sum = (as: Array<number>) => as.reduce((a, acc) => a + acc, 0)
 *
 * // Sum the values in a tree:
 * assert.deepStrictEqual(fold((a: number, bs: Array<number>) => a + sum(bs))(t), 6)
 *
 * // Find the maximum value in the tree:
 * assert.deepStrictEqual(fold((a: number, bs: Array<number>) => bs.reduce((b, acc) => Math.max(b, acc), a))(t), 3)
 *
 * // Count the number of leaves in the tree:
 * assert.deepStrictEqual(fold((_: number, bs: Array<number>) => (bs.length === 0 ? 1 : sum(bs)))(t), 2)
 *
 * @category destructors
 * @since 2.6.0
 */
export declare function fold<A, B>(f: (a: A, bs: Array<B>) => B): (tree: Tree<A>) => B
/**
 * Apply a function to an argument under a type constructor.
 *
 * @category Apply
 * @since 2.0.0
 */
export declare const ap: <A>(fa: Tree<A>) => <B>(fab: Tree<(a: A) => B>) => Tree<B>
/**
 * Combine two effectful actions, keeping only the result of the first.
 *
 * Derivable from `Apply`.
 *
 * @category combinators
 * @since 2.0.0
 */
export declare const apFirst: <B>(fb: Tree<B>) => <A>(fa: Tree<A>) => Tree<A>
/**
 * Combine two effectful actions, keeping only the result of the second.
 *
 * Derivable from `Apply`.
 *
 * @category combinators
 * @since 2.0.0
 */
export declare const apSecond: <B>(fb: Tree<B>) => <A>(fa: Tree<A>) => Tree<B>
/**
 * Composes computations in sequence, using the return value of one computation to determine the next computation.
 *
 * @category Monad
 * @since 2.0.0
 */
export declare const chain: <A, B>(f: (a: A) => Tree<B>) => (ma: Tree<A>) => Tree<B>
/**
 * Composes computations in sequence, using the return value of one computation to determine the next computation and
 * keeping only the result of the first.
 *
 * Derivable from `Monad`.
 *
 * @category combinators
 * @since 2.0.0
 */
export declare const chainFirst: <A, B>(f: (a: A) => Tree<B>) => (ma: Tree<A>) => Tree<A>
/**
 * @category Extend
 * @since 2.0.0
 */
export declare const extend: <A, B>(f: (wa: Tree<A>) => B) => (wa: Tree<A>) => Tree<B>
/**
 * Derivable from `Extend`.
 *
 * @category combinators
 * @since 2.0.0
 */
export declare const duplicate: <A>(wa: Tree<A>) => Tree<Tree<A>>
/**
 * Derivable from `Monad`.
 *
 * @category combinators
 * @since 2.0.0
 */
export declare const flatten: <A>(mma: Tree<Tree<A>>) => Tree<A>
/**
 * `map` can be used to turn functions `(a: A) => B` into functions `(fa: F<A>) => F<B>` whose argument and return types
 * use the type constructor `F` to represent some computational context.
 *
 * @category Functor
 * @since 2.0.0
 */
export declare const map: <A, B>(f: (a: A) => B) => (fa: Tree<A>) => Tree<B>
/**
 * @category Foldable
 * @since 2.0.0
 */
export declare const reduce: <A, B>(b: B, f: (b: B, a: A) => B) => (fa: Tree<A>) => B
/**
 * @category Foldable
 * @since 2.0.0
 */
export declare const foldMap: <M>(M: Monoid<M>) => <A>(f: (a: A) => M) => (fa: Tree<A>) => M
/**
 * @category Foldable
 * @since 2.0.0
 */
export declare const reduceRight: <A, B>(b: B, f: (a: A, b: B) => B) => (fa: Tree<A>) => B
/**
 * @category Extract
 * @since 2.6.2
 */
export declare const extract: <A>(wa: Tree<A>) => A
/**
 * @since 2.6.3
 */
export declare const traverse: PipeableTraverse1<URI>
/**
 * @since 2.6.3
 */
export declare const sequence: Traversable1<URI>['sequence']
/**
 * Wrap a value into the type constructor.
 *
 * @category Applicative
 * @since 2.7.0
 */
export declare const of: Applicative1<URI>['of']
/**
 * @category instances
 * @since 2.0.0
 */
export declare const URI = 'Tree'
/**
 * @category instances
 * @since 2.0.0
 */
export declare type URI = typeof URI
declare module './HKT' {
  interface URItoKind<A> {
    readonly [URI]: Tree<A>
  }
}
/**
 * @category instances
 * @since 2.7.0
 */
export declare const Functor: Functor1<URI>
/**
 * @category instances
 * @since 2.7.0
 */
export declare const Applicative: Applicative1<URI>
/**
 * @category instances
 * @since 2.7.0
 */
export declare const Monad: Monad1<URI>
/**
 * @category instances
 * @since 2.7.0
 */
export declare const Foldable: Foldable1<URI>
/**
 * @category instances
 * @since 2.7.0
 */
export declare const Traversable: Traversable1<URI>
/**
 * @category instances
 * @since 2.7.0
 */
export declare const Comonad: Comonad1<URI>
/**
 * @category instances
 * @since 2.0.0
 */
export declare const tree: Monad1<URI> & Foldable1<URI> & Traversable1<URI> & Comonad1<URI>
/**
 * @since 2.9.0
 */
export declare const Do: Tree<{}>
/**
 * @since 2.8.0
 */
export declare const bindTo: <N extends string>(name: N) => <A>(fa: Tree<A>) => Tree<{ [K in N]: A }>
/**
 * @since 2.8.0
 */
export declare const bind: <N extends string, A, B>(
  name: Exclude<N, keyof A>,
  f: (a: A) => Tree<B>
) => (fa: Tree<A>) => Tree<{ [K in N | keyof A]: K extends keyof A ? A[K] : B }>
/**
 * @since 2.8.0
 */
export declare const apS: <A, N extends string, B>(
  name: Exclude<N, keyof A>,
  fb: Tree<B>
) => (fa: Tree<A>) => Tree<{ [K in N | keyof A]: K extends keyof A ? A[K] : B }>