/**
 * @since 1.0.0
 */
import type { TypeLambda } from "@fp-ts/core/HKT";
/**
 * @category type lambdas
 * @since 1.0.0
 */
export interface FunctionTypeLambda extends TypeLambda {
    readonly type: (a: this["In"]) => this["Target"];
}
/**
 * Tests if a value is a `function`.
 *
 * @param input - The value to test.
 *
 * @example
 * import { isFunction } from '@fp-ts/core/Predicate'
 *
 * assert.deepStrictEqual(isFunction(isFunction), true)
 * assert.deepStrictEqual(isFunction("function"), false)
 *
 * @category guards
 * @since 1.0.0
 */
export declare const isFunction: (input: unknown) => input is Function;
/**
 * Creates a function that is both data-last and data-first.
 *
 * @since 1.0.0
 */
export declare const dual: <DataLast extends (...args: Array<any>) => any, DataFirst extends (...args: Array<any>) => any>(dataFirstArity: Parameters<DataFirst>["length"], body: DataFirst) => DataLast & DataFirst;
/**
 * Apply a function to a given value.
 *
 * @example
 * import { pipe, apply } from '@fp-ts/core/Function'
 * import { increment } from '@fp-ts/core/Number'
 *
 * assert.deepStrictEqual(pipe(2, apply(increment)), 3)
 *
 * @since 1.0.0
 */
export declare const apply: <A, B>(self: (a: A) => B) => (a: A) => B;
/**
 * A lazy argument
 *
 * @since 1.0.0
 */
export interface LazyArg<A> {
    (): A;
}
/**
 * @example
 * import { FunctionN } from '@fp-ts/core/Function'
 *
 * export const sum: FunctionN<[number, number], number> = (a, b) => a + b
 *
 * @since 1.0.0
 */
export interface FunctionN<A extends ReadonlyArray<unknown>, B> {
    (...args: A): B;
}
/**
 * @since 1.0.0
 */
export declare const identity: <A>(a: A) => A;
/**
 * @since 1.0.0
 */
export declare const unsafeCoerce: <A, B>(a: A) => B;
/**
 * Creates a constant value that never changes.
 *
 * This is useful when you want to pass a value to a higher-order function (a function that takes another function as its argument)
 * and want that inner function to always use the same value, no matter how many times it is called.
 *
 * @param value - The constant value to be returned
 *
 * @since 1.0.0
 */
export declare const constant: <A>(value: A) => LazyArg<A>;
/**
 * A thunk that returns always `true`.
 *
 * @since 1.0.0
 */
export declare const constTrue: LazyArg<boolean>;
/**
 * A thunk that returns always `false`.
 *
 * @since 1.0.0
 */
export declare const constFalse: LazyArg<boolean>;
/**
 * A thunk that returns always `null`.
 *
 * @since 1.0.0
 */
export declare const constNull: LazyArg<null>;
/**
 * A thunk that returns always `undefined`.
 *
 * @since 1.0.0
 */
export declare const constUndefined: LazyArg<undefined>;
/**
 * A thunk that returns always `void`.
 *
 * @since 1.0.0
 */
export declare const constVoid: LazyArg<void>;
/**
 * Reverses the order of arguments for a curried function.
 *
 * @param f -A curried function that takes multiple arguments.
 *
 * @example
 * import { flip } from '@fp-ts/core/Function'
 *
 * const f = (a: number) => (b: string) => a - b.length
 *
 * assert.deepStrictEqual(flip(f)('aaa')(2), -1)
 *
 * @since 1.0.0
 */
export declare const flip: <A extends unknown[], B extends unknown[], C>(f: (...a: A) => (...b: B) => C) => (...b: B) => (...a: A) => C;
/**
 * Performs left-to-right function composition. The first argument may have any arity, the remaining arguments must be unary.
 *
 * @example
 * import { flow } from '@fp-ts/core/Function'
 *
 * const len = (s: string): number => s.length
 * const double = (n: number): number => n * 2
 *
 * const f = flow(len, double)
 *
 * assert.deepStrictEqual(f('aaa'), 6)
 *
 * @see {@link pipe}
 * @since 1.0.0
 */
export declare function flow<A extends ReadonlyArray<unknown>, B>(ab: (...a: A) => B): (...a: A) => B;
export declare function flow<A extends ReadonlyArray<unknown>, B, C>(ab: (...a: A) => B, bc: (b: B) => C): (...a: A) => C;
export declare function flow<A extends ReadonlyArray<unknown>, B, C, D>(ab: (...a: A) => B, bc: (b: B) => C, cd: (c: C) => D): (...a: A) => D;
export declare function flow<A extends ReadonlyArray<unknown>, B, C, D, E>(ab: (...a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E): (...a: A) => E;
export declare function flow<A extends ReadonlyArray<unknown>, B, C, D, E, F>(ab: (...a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F): (...a: A) => F;
export declare function flow<A extends ReadonlyArray<unknown>, B, C, D, E, F, G>(ab: (...a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G): (...a: A) => G;
export declare function flow<A extends ReadonlyArray<unknown>, B, C, D, E, F, G, H>(ab: (...a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G, gh: (g: G) => H): (...a: A) => H;
export declare function flow<A extends ReadonlyArray<unknown>, B, C, D, E, F, G, H, I>(ab: (...a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G, gh: (g: G) => H, hi: (h: H) => I): (...a: A) => I;
export declare function flow<A extends ReadonlyArray<unknown>, B, C, D, E, F, G, H, I, J>(ab: (...a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G, gh: (g: G) => H, hi: (h: H) => I, ij: (i: I) => J): (...a: A) => J;
/**
 * Composes two functions, `ab` and `bc` into a single function that takes in an argument `a` of type `A` and returns a result of type `C`.
 * The result is obtained by first applying the `ab` function to `a` and then applying the `bc` function to the result of `ab`.
 *
 * @param ab - A function that maps from `A` to `B`.
 * @param bc - A function that maps from `B` to `C`.
 *
 * @example
 * import { compose } from '@fp-ts/core/Function'
 *
 * const inc = (n: number) => n + 1;
 * const square = (n: number) => n * n;
 *
 * assert.strictEqual(compose(inc, square)(2), 9);
 *
 * @since 1.0.0
 */
export declare const compose: {
    <B, C>(bc: (b: B) => C): <A>(self: (a: A) => B) => (a: A) => C;
    <A, B, C>(self: (a: A) => B, bc: (b: B) => C): (a: A) => C;
};
/**
 * The `absurd` function is a stub for cases where a value of type `never` is encountered in your code,
 * meaning that it should be impossible for this code to be executed.
 *
 * This function is particularly useful in functional programming, where it's often necessary to specify that certain cases are impossible.
 * By calling `absurd`, you can ensure that the type system correctly reflects that a certain value should never occur.
 *
 * @since 1.0.0
 */
export declare const absurd: <A>(_: never) => A;
/**
 * Creates a tupled version of this function: instead of `n` arguments, it accepts a single tuple argument.
 *
 * @example
 * import { tupled } from '@fp-ts/core/Function'
 *
 * const add = tupled((x: number, y: number): number => x + y)
 *
 * assert.deepStrictEqual(add([1, 2]), 3)
 *
 * @since 1.0.0
 */
export declare const tupled: <A extends readonly unknown[], B>(f: (...a: A) => B) => (a: A) => B;
/**
 * Inverse function of `tupled`
 *
 * @since 1.0.0
 */
export declare const untupled: <A extends readonly unknown[], B>(f: (a: A) => B) => (...a: A) => B;
/**
 * Pipes the value of an expression into a pipeline of functions.
 *
 * @example
 * import { pipe } from '@fp-ts/core/Function'
 *
 * const len = (s: string): number => s.length
 * const double = (n: number): number => n * 2
 *
 * assert.deepStrictEqual(pipe('aaa', len, double), 6)
 *
 * @see {@link flow}
 * @since 1.0.0
 */
export declare function pipe<A>(a: A): A;
export declare function pipe<A, B>(a: A, ab: (a: A) => B): B;
export declare function pipe<A, B, C>(a: A, ab: (a: A) => B, bc: (b: B) => C): C;
export declare function pipe<A, B, C, D>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D): D;
export declare function pipe<A, B, C, D, E>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E): E;
export declare function pipe<A, B, C, D, E, F>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F): F;
export declare function pipe<A, B, C, D, E, F, G>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G): G;
export declare function pipe<A, B, C, D, E, F, G, H>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G, gh: (g: G) => H): H;
export declare function pipe<A, B, C, D, E, F, G, H, I>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G, gh: (g: G) => H, hi: (h: H) => I): I;
export declare function pipe<A, B, C, D, E, F, G, H, I, J>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G, gh: (g: G) => H, hi: (h: H) => I, ij: (i: I) => J): J;
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G, gh: (g: G) => H, hi: (h: H) => I, ij: (i: I) => J, jk: (j: J) => K): K;
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K, L>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G, gh: (g: G) => H, hi: (h: H) => I, ij: (i: I) => J, jk: (j: J) => K, kl: (k: K) => L): L;
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K, L, M>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G, gh: (g: G) => H, hi: (h: H) => I, ij: (i: I) => J, jk: (j: J) => K, kl: (k: K) => L, lm: (l: L) => M): M;
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K, L, M, N>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G, gh: (g: G) => H, hi: (h: H) => I, ij: (i: I) => J, jk: (j: J) => K, kl: (k: K) => L, lm: (l: L) => M, mn: (m: M) => N): N;
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K, L, M, N, O>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G, gh: (g: G) => H, hi: (h: H) => I, ij: (i: I) => J, jk: (j: J) => K, kl: (k: K) => L, lm: (l: L) => M, mn: (m: M) => N, no: (n: N) => O): O;
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G, gh: (g: G) => H, hi: (h: H) => I, ij: (i: I) => J, jk: (j: J) => K, kl: (k: K) => L, lm: (l: L) => M, mn: (m: M) => N, no: (n: N) => O, op: (o: O) => P): P;
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G, gh: (g: G) => H, hi: (h: H) => I, ij: (i: I) => J, jk: (j: J) => K, kl: (k: K) => L, lm: (l: L) => M, mn: (m: M) => N, no: (n: N) => O, op: (o: O) => P, pq: (p: P) => Q): Q;
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G, gh: (g: G) => H, hi: (h: H) => I, ij: (i: I) => J, jk: (j: J) => K, kl: (k: K) => L, lm: (l: L) => M, mn: (m: M) => N, no: (n: N) => O, op: (o: O) => P, pq: (p: P) => Q, qr: (q: Q) => R): R;
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G, gh: (g: G) => H, hi: (h: H) => I, ij: (i: I) => J, jk: (j: J) => K, kl: (k: K) => L, lm: (l: L) => M, mn: (m: M) => N, no: (n: N) => O, op: (o: O) => P, pq: (p: P) => Q, qr: (q: Q) => R, rs: (r: R) => S): S;
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G, gh: (g: G) => H, hi: (h: H) => I, ij: (i: I) => J, jk: (j: J) => K, kl: (k: K) => L, lm: (l: L) => M, mn: (m: M) => N, no: (n: N) => O, op: (o: O) => P, pq: (p: P) => Q, qr: (q: Q) => R, rs: (r: R) => S, st: (s: S) => T): T;
/**
 * Type hole simulation
 *
 * @since 1.0.0
 */
export declare const hole: <T>() => T;
/**
 * The SK combinator, also known as the "S-K combinator" or "S-combinator", is a fundamental combinator in the
 * lambda calculus and the SKI combinator calculus.
 *
 * This function is useful for discarding the first argument passed to it and returning the second argument.
 *
 * @param _ - The first argument to be discarded.
 * @param b - The second argument to be returned.
 *
 * @example
 * import { SK } from '@fp-ts/core/Function';
 *
 * assert.deepStrictEqual(SK(0, 'hello'), 'hello')
 *
 * @since 1.0.0
 */
export declare const SK: <A, B>(_: A, b: B) => B;
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