import { getApplicativeMonoid } from './Applicative';
import { apFirst as apFirst_, apS as apS_, apSecond as apSecond_, getApplySemigroup as getApplySemigroup_ } from './Apply';
import { bind as bind_, chainFirst as chainFirst_ } from './Chain';
import { tailRec } from './ChainRec';
import { chainOptionK as chainOptionK_, filterOrElse as filterOrElse_, fromOption as fromOption_, fromOptionK as fromOptionK_, fromPredicate as fromPredicate_ } from './FromEither';
import { flow, identity, pipe } from './function';
import { bindTo as bindTo_, flap as flap_, let as let__ } from './Functor';
import * as _ from './internal';
import { separated } from './Separated';
import { wiltDefault, witherDefault } from './Witherable';
// -------------------------------------------------------------------------------------
// constructors
// -------------------------------------------------------------------------------------
/**
 * Constructs a new `Either` holding a `Left` value. This usually represents a failure, due to the right-bias of this
 * structure.
 *
 * @category constructors
 * @since 2.0.0
 */
export var left = _.left;
/**
 * Constructs a new `Either` holding a `Right` value. This usually represents a successful value due to the right bias
 * of this structure.
 *
 * @category constructors
 * @since 2.0.0
 */
export var right = _.right;
var _map = function (fa, f) { return pipe(fa, map(f)); };
var _ap = function (fab, fa) { return pipe(fab, ap(fa)); };
/* istanbul ignore next */
var _chain = function (ma, f) { return pipe(ma, chain(f)); };
/* istanbul ignore next */
var _reduce = function (fa, b, f) { return pipe(fa, reduce(b, f)); };
/* istanbul ignore next */
var _foldMap = function (M) { return function (fa, f) {
    var foldMapM = foldMap(M);
    return pipe(fa, foldMapM(f));
}; };
/* istanbul ignore next */
var _reduceRight = function (fa, b, f) { return pipe(fa, reduceRight(b, f)); };
var _traverse = function (F) {
    var traverseF = traverse(F);
    return function (ta, f) { return pipe(ta, traverseF(f)); };
};
var _bimap = function (fa, f, g) { return pipe(fa, bimap(f, g)); };
var _mapLeft = function (fa, f) { return pipe(fa, mapLeft(f)); };
/* istanbul ignore next */
var _alt = function (fa, that) { return pipe(fa, alt(that)); };
/* istanbul ignore next */
var _extend = function (wa, f) { return pipe(wa, extend(f)); };
var _chainRec = function (a, f) {
    return tailRec(f(a), function (e) {
        return isLeft(e) ? right(left(e.left)) : isLeft(e.right) ? left(f(e.right.left)) : right(right(e.right.right));
    });
};
/**
 * @category type lambdas
 * @since 2.0.0
 */
export var URI = 'Either';
/**
 * @category instances
 * @since 2.0.0
 */
export var getShow = function (SE, SA) { return ({
    show: function (ma) { return (isLeft(ma) ? "left(".concat(SE.show(ma.left), ")") : "right(".concat(SA.show(ma.right), ")")); }
}); };
/**
 * @category instances
 * @since 2.0.0
 */
export var getEq = function (EL, EA) { return ({
    equals: function (x, y) {
        return x === y || (isLeft(x) ? isLeft(y) && EL.equals(x.left, y.left) : isRight(y) && EA.equals(x.right, y.right));
    }
}); };
/**
 * Semigroup returning the left-most non-`Left` value. If both operands are `Right`s then the inner values are
 * concatenated using the provided `Semigroup`
 *
 * @example
 * import { getSemigroup, left, right } from 'fp-ts/Either'
 * import { SemigroupSum } from 'fp-ts/number'
 *
 * const S = getSemigroup<string, number>(SemigroupSum)
 * assert.deepStrictEqual(S.concat(left('a'), left('b')), left('a'))
 * assert.deepStrictEqual(S.concat(left('a'), right(2)), right(2))
 * assert.deepStrictEqual(S.concat(right(1), left('b')), right(1))
 * assert.deepStrictEqual(S.concat(right(1), right(2)), right(3))
 *
 * @category instances
 * @since 2.0.0
 */
export var getSemigroup = function (S) { return ({
    concat: function (x, y) { return (isLeft(y) ? x : isLeft(x) ? y : right(S.concat(x.right, y.right))); }
}); };
/**
 * Builds a `Compactable` instance for `Either` given `Monoid` for the left side.
 *
 * @category filtering
 * @since 2.10.0
 */
export var getCompactable = function (M) {
    var empty = left(M.empty);
    return {
        URI: URI,
        _E: undefined,
        compact: function (ma) { return (isLeft(ma) ? ma : ma.right._tag === 'None' ? empty : right(ma.right.value)); },
        separate: function (ma) {
            return isLeft(ma)
                ? separated(ma, ma)
                : isLeft(ma.right)
                    ? separated(right(ma.right.left), empty)
                    : separated(empty, right(ma.right.right));
        }
    };
};
/**
 * Builds a `Filterable` instance for `Either` given `Monoid` for the left side
 *
 * @category filtering
 * @since 2.10.0
 */
export var getFilterable = function (M) {
    var empty = left(M.empty);
    var _a = getCompactable(M), compact = _a.compact, separate = _a.separate;
    var filter = function (ma, predicate) {
        return isLeft(ma) ? ma : predicate(ma.right) ? ma : empty;
    };
    var partition = function (ma, p) {
        return isLeft(ma)
            ? separated(ma, ma)
            : p(ma.right)
                ? separated(empty, right(ma.right))
                : separated(right(ma.right), empty);
    };
    return {
        URI: URI,
        _E: undefined,
        map: _map,
        compact: compact,
        separate: separate,
        filter: filter,
        filterMap: function (ma, f) {
            if (isLeft(ma)) {
                return ma;
            }
            var ob = f(ma.right);
            return ob._tag === 'None' ? empty : right(ob.value);
        },
        partition: partition,
        partitionMap: function (ma, f) {
            if (isLeft(ma)) {
                return separated(ma, ma);
            }
            var e = f(ma.right);
            return isLeft(e) ? separated(right(e.left), empty) : separated(empty, right(e.right));
        }
    };
};
/**
 * Builds `Witherable` instance for `Either` given `Monoid` for the left side
 *
 * @category filtering
 * @since 2.0.0
 */
export var getWitherable = function (M) {
    var F_ = getFilterable(M);
    var C = getCompactable(M);
    return {
        URI: URI,
        _E: undefined,
        map: _map,
        compact: F_.compact,
        separate: F_.separate,
        filter: F_.filter,
        filterMap: F_.filterMap,
        partition: F_.partition,
        partitionMap: F_.partitionMap,
        traverse: _traverse,
        sequence: sequence,
        reduce: _reduce,
        foldMap: _foldMap,
        reduceRight: _reduceRight,
        wither: witherDefault(Traversable, C),
        wilt: wiltDefault(Traversable, C)
    };
};
/**
 * The default [`Applicative`](#applicative) instance returns the first error, if you want to
 * get all errors you need to provide a way to concatenate them via a `Semigroup`.
 *
 * @example
 * import * as A from 'fp-ts/Apply'
 * import * as E from 'fp-ts/Either'
 * import { pipe } from 'fp-ts/function'
 * import * as S from 'fp-ts/Semigroup'
 * import * as string from 'fp-ts/string'
 *
 * const parseString = (u: unknown): E.Either<string, string> =>
 *   typeof u === 'string' ? E.right(u) : E.left('not a string')
 *
 * const parseNumber = (u: unknown): E.Either<string, number> =>
 *   typeof u === 'number' ? E.right(u) : E.left('not a number')
 *
 * interface Person {
 *   readonly name: string
 *   readonly age: number
 * }
 *
 * const parsePerson = (
 *   input: Record<string, unknown>
 * ): E.Either<string, Person> =>
 *   pipe(
 *     E.Do,
 *     E.apS('name', parseString(input.name)),
 *     E.apS('age', parseNumber(input.age))
 *   )
 *
 * assert.deepStrictEqual(parsePerson({}), E.left('not a string')) // <= first error
 *
 * const Applicative = E.getApplicativeValidation(
 *   pipe(string.Semigroup, S.intercalate(', '))
 * )
 *
 * const apS = A.apS(Applicative)
 *
 * const parsePersonAll = (
 *   input: Record<string, unknown>
 * ): E.Either<string, Person> =>
 *   pipe(
 *     E.Do,
 *     apS('name', parseString(input.name)),
 *     apS('age', parseNumber(input.age))
 *   )
 *
 * assert.deepStrictEqual(parsePersonAll({}), E.left('not a string, not a number')) // <= all errors
 *
 * @category error handling
 * @since 2.7.0
 */
export var getApplicativeValidation = function (SE) { return ({
    URI: URI,
    _E: undefined,
    map: _map,
    ap: function (fab, fa) {
        return isLeft(fab)
            ? isLeft(fa)
                ? left(SE.concat(fab.left, fa.left))
                : fab
            : isLeft(fa)
                ? fa
                : right(fab.right(fa.right));
    },
    of: of
}); };
/**
 * The default [`Alt`](#alt) instance returns the last error, if you want to
 * get all errors you need to provide a way to concatenate them via a `Semigroup`.
 *
 * @example
 * import * as E from 'fp-ts/Either'
 * import { pipe } from 'fp-ts/function'
 * import * as S from 'fp-ts/Semigroup'
 * import * as string from 'fp-ts/string'
 *
 * const parseString = (u: unknown): E.Either<string, string> =>
 *   typeof u === 'string' ? E.right(u) : E.left('not a string')
 *
 * const parseNumber = (u: unknown): E.Either<string, number> =>
 *   typeof u === 'number' ? E.right(u) : E.left('not a number')
 *
 * const parse = (u: unknown): E.Either<string, string | number> =>
 *   pipe(
 *     parseString(u),
 *     E.alt<string, string | number>(() => parseNumber(u))
 *   )
 *
 * assert.deepStrictEqual(parse(true), E.left('not a number')) // <= last error
 *
 * const Alt = E.getAltValidation(pipe(string.Semigroup, S.intercalate(', ')))
 *
 * const parseAll = (u: unknown): E.Either<string, string | number> =>
 *   Alt.alt<string | number>(parseString(u), () => parseNumber(u))
 *
 * assert.deepStrictEqual(parseAll(true), E.left('not a string, not a number')) // <= all errors
 *
 * @category error handling
 * @since 2.7.0
 */
export var getAltValidation = function (SE) { return ({
    URI: URI,
    _E: undefined,
    map: _map,
    alt: function (me, that) {
        if (isRight(me)) {
            return me;
        }
        var ea = that();
        return isLeft(ea) ? left(SE.concat(me.left, ea.left)) : ea;
    }
}); };
/**
 * @category mapping
 * @since 2.0.0
 */
export var map = function (f) { return function (fa) {
    return isLeft(fa) ? fa : right(f(fa.right));
}; };
/**
 * @category instances
 * @since 2.7.0
 */
export var Functor = {
    URI: URI,
    map: _map
};
/**
 * @category constructors
 * @since 2.7.0
 */
export var of = right;
/**
 * @category instances
 * @since 2.10.0
 */
export var Pointed = {
    URI: URI,
    of: of
};
/**
 * Less strict version of [`ap`](#ap).
 *
 * The `W` suffix (short for **W**idening) means that the error types will be merged.
 *
 * @since 2.8.0
 */
export var apW = function (fa) { return function (fab) {
    return isLeft(fab) ? fab : isLeft(fa) ? fa : right(fab.right(fa.right));
}; };
/**
 * @since 2.0.0
 */
export var ap = apW;
/**
 * @category instances
 * @since 2.10.0
 */
export var Apply = {
    URI: URI,
    map: _map,
    ap: _ap
};
/**
 * @category instances
 * @since 2.7.0
 */
export var Applicative = {
    URI: URI,
    map: _map,
    ap: _ap,
    of: of
};
/**
 * Less strict version of [`chain`](#chain).
 *
 * The `W` suffix (short for **W**idening) means that the error types will be merged.
 *
 * @example
 * import * as E from 'fp-ts/Either'
 * import { pipe } from 'fp-ts/function'
 *
 * const e1: E.Either<string, number> = E.right(1)
 * const e2: E.Either<number, number> = E.right(2)
 *
 * export const result1 = pipe(
 *   // @ts-expect-error
 *   e1,
 *   E.chain(() => e2)
 * )
 *
 * // merged error types -----v-------------v
 * // const result2: E.Either<string | number, number>
 * export const result2 = pipe(
 *   e1, // no error
 *   E.chainW(() => e2)
 * )
 *
 * @category sequencing
 * @since 2.6.0
 */
export var chainW = function (f) {
    return function (ma) {
        return isLeft(ma) ? ma : f(ma.right);
    };
};
/**
 * Composes computations in sequence, using the return value of one computation to determine the next computation.
 *
 * @category sequencing
 * @since 2.0.0
 */
export var chain = chainW;
/**
 * @category instances
 * @since 2.10.0
 */
export var Chain = {
    URI: URI,
    map: _map,
    ap: _ap,
    chain: _chain
};
/**
 * @category instances
 * @since 2.7.0
 */
export var Monad = {
    URI: URI,
    map: _map,
    ap: _ap,
    of: of,
    chain: _chain
};
/**
 * Left-associative fold of a structure.
 *
 * @example
 * import { pipe } from 'fp-ts/function'
 * import * as E from 'fp-ts/Either'
 *
 * const startWith = 'prefix'
 * const concat = (a: string, b: string) => `${a}:${b}`
 *
 * assert.deepStrictEqual(
 *   pipe(E.right('a'), E.reduce(startWith, concat)),
 *   'prefix:a'
 * )
 *
 * assert.deepStrictEqual(
 *   pipe(E.left('e'), E.reduce(startWith, concat)),
 *   'prefix'
 * )
 *
 * @category folding
 * @since 2.0.0
 */
export var reduce = function (b, f) { return function (fa) {
    return isLeft(fa) ? b : f(b, fa.right);
}; };
/**
 * Map each element of the structure to a monoid, and combine the results.
 *
 * @example
 * import { pipe } from 'fp-ts/function'
 * import * as E from 'fp-ts/Either'
 * import * as S from 'fp-ts/string'
 *
 * const yell = (a: string) => `${a}!`
 *
 * assert.deepStrictEqual(
 *   pipe(E.right('a'), E.foldMap(S.Monoid)(yell)),
 *   'a!'
 * )
 *
 * assert.deepStrictEqual(
 *   pipe(E.left('e'), E.foldMap(S.Monoid)(yell)),
 *   S.Monoid.empty
 * )
 *
 * @category folding
 * @since 2.0.0
 */
export var foldMap = function (M) { return function (f) { return function (fa) {
    return isLeft(fa) ? M.empty : f(fa.right);
}; }; };
/**
 * Right-associative fold of a structure.
 *
 * @example
 * import { pipe } from 'fp-ts/function'
 * import * as E from 'fp-ts/Either'
 *
 * const startWith = 'postfix'
 * const concat = (a: string, b: string) => `${a}:${b}`
 *
 * assert.deepStrictEqual(
 *   pipe(E.right('a'), E.reduceRight(startWith, concat)),
 *   'a:postfix'
 * )
 *
 * assert.deepStrictEqual(
 *   pipe(E.left('e'), E.reduceRight(startWith, concat)),
 *   'postfix'
 * )
 *
 * @category folding
 * @since 2.0.0
 */
export var reduceRight = function (b, f) { return function (fa) {
    return isLeft(fa) ? b : f(fa.right, b);
}; };
/**
 * @category instances
 * @since 2.7.0
 */
export var Foldable = {
    URI: URI,
    reduce: _reduce,
    foldMap: _foldMap,
    reduceRight: _reduceRight
};
/**
 * Map each element of a structure to an action, evaluate these actions from left to right, and collect the results.
 *
 * @example
 * import { pipe } from 'fp-ts/function'
 * import * as RA from 'fp-ts/ReadonlyArray'
 * import * as E from 'fp-ts/Either'
 * import * as O from 'fp-ts/Option'
 *
 * assert.deepStrictEqual(
 *   pipe(E.right(['a']), E.traverse(O.Applicative)(RA.head)),
 *   O.some(E.right('a'))
 *  )
 *
 * assert.deepStrictEqual(
 *   pipe(E.right([]), E.traverse(O.Applicative)(RA.head)),
 *   O.none
 * )
 *
 * @category traversing
 * @since 2.6.3
 */
export var traverse = function (F) {
    return function (f) {
        return function (ta) {
            return isLeft(ta) ? F.of(left(ta.left)) : F.map(f(ta.right), right);
        };
    };
};
/**
 * Evaluate each monadic action in the structure from left to right, and collect the results.
 *
 * @example
 * import { pipe } from 'fp-ts/function'
 * import * as E from 'fp-ts/Either'
 * import * as O from 'fp-ts/Option'
 *
 * assert.deepStrictEqual(
 *   pipe(E.right(O.some('a')), E.sequence(O.Applicative)),
 *   O.some(E.right('a'))
 *  )
 *
 * assert.deepStrictEqual(
 *   pipe(E.right(O.none), E.sequence(O.Applicative)),
 *   O.none
 * )
 *
 * @category traversing
 * @since 2.6.3
 */
export var sequence = function (F) {
    return function (ma) {
        return isLeft(ma) ? F.of(left(ma.left)) : F.map(ma.right, right);
    };
};
/**
 * @category instances
 * @since 2.7.0
 */
export var Traversable = {
    URI: URI,
    map: _map,
    reduce: _reduce,
    foldMap: _foldMap,
    reduceRight: _reduceRight,
    traverse: _traverse,
    sequence: sequence
};
/**
 * Map a pair of functions over the two type arguments of the bifunctor.
 *
 * @category mapping
 * @since 2.0.0
 */
export var bimap = function (f, g) { return function (fa) {
    return isLeft(fa) ? left(f(fa.left)) : right(g(fa.right));
}; };
/**
 * Map a function over the first type argument of a bifunctor.
 *
 * @category error handling
 * @since 2.0.0
 */
export var mapLeft = function (f) { return function (fa) {
    return isLeft(fa) ? left(f(fa.left)) : fa;
}; };
/**
 * @category instances
 * @since 2.7.0
 */
export var Bifunctor = {
    URI: URI,
    bimap: _bimap,
    mapLeft: _mapLeft
};
/**
 * Less strict version of [`alt`](#alt).
 *
 * The `W` suffix (short for **W**idening) means that the error and the return types will be merged.
 *
 * @category error handling
 * @since 2.9.0
 */
export var altW = function (that) { return function (fa) {
    return isLeft(fa) ? that() : fa;
}; };
/**
 * Identifies an associative operation on a type constructor. It is similar to `Semigroup`, except that it applies to
 * types of kind `* -> *`.
 *
 * In case of `Either` returns the left-most non-`Left` value (or the right-most `Left` value if both values are `Left`).
 *
 * | x        | y        | pipe(x, alt(() => y) |
 * | -------- | -------- | -------------------- |
 * | left(a)  | left(b)  | left(b)              |
 * | left(a)  | right(2) | right(2)             |
 * | right(1) | left(b)  | right(1)             |
 * | right(1) | right(2) | right(1)             |
 *
 * @example
 * import * as E from 'fp-ts/Either'
 * import { pipe } from 'fp-ts/function'
 *
 * assert.deepStrictEqual(
 *   pipe(
 *     E.left('a'),
 *     E.alt(() => E.left('b'))
 *   ),
 *   E.left('b')
 * )
 * assert.deepStrictEqual(
 *   pipe(
 *     E.left('a'),
 *     E.alt(() => E.right(2))
 *   ),
 *   E.right(2)
 * )
 * assert.deepStrictEqual(
 *   pipe(
 *     E.right(1),
 *     E.alt(() => E.left('b'))
 *   ),
 *   E.right(1)
 * )
 * assert.deepStrictEqual(
 *   pipe(
 *     E.right(1),
 *     E.alt(() => E.right(2))
 *   ),
 *   E.right(1)
 * )
 *
 * @category error handling
 * @since 2.0.0
 */
export var alt = altW;
/**
 * @category instances
 * @since 2.7.0
 */
export var Alt = {
    URI: URI,
    map: _map,
    alt: _alt
};
/**
 * @since 2.0.0
 */
export var extend = function (f) { return function (wa) {
    return isLeft(wa) ? wa : right(f(wa));
}; };
/**
 * @category instances
 * @since 2.7.0
 */
export var Extend = {
    URI: URI,
    map: _map,
    extend: _extend
};
/**
 * @category instances
 * @since 2.7.0
 */
export var ChainRec = {
    URI: URI,
    map: _map,
    ap: _ap,
    chain: _chain,
    chainRec: _chainRec
};
/**
 * @since 2.6.3
 */
export var throwError = left;
/**
 * @category instances
 * @since 2.7.0
 */
export var MonadThrow = {
    URI: URI,
    map: _map,
    ap: _ap,
    of: of,
    chain: _chain,
    throwError: throwError
};
/**
 * @category instances
 * @since 2.10.0
 */
export var FromEither = {
    URI: URI,
    fromEither: identity
};
/**
 * @example
 * import { fromPredicate, left, right } from 'fp-ts/Either'
 * import { pipe } from 'fp-ts/function'
 *
 * assert.deepStrictEqual(
 *   pipe(
 *     1,
 *     fromPredicate(
 *       (n) => n > 0,
 *       () => 'error'
 *     )
 *   ),
 *   right(1)
 * )
 * assert.deepStrictEqual(
 *   pipe(
 *     -1,
 *     fromPredicate(
 *       (n) => n > 0,
 *       () => 'error'
 *     )
 *   ),
 *   left('error')
 * )
 *
 * @category lifting
 * @since 2.0.0
 */
export var fromPredicate = /*#__PURE__*/ fromPredicate_(FromEither);
// -------------------------------------------------------------------------------------
// conversions
// -------------------------------------------------------------------------------------
/**
 * @example
 * import * as E from 'fp-ts/Either'
 * import { pipe } from 'fp-ts/function'
 * import * as O from 'fp-ts/Option'
 *
 * assert.deepStrictEqual(
 *   pipe(
 *     O.some(1),
 *     E.fromOption(() => 'error')
 *   ),
 *   E.right(1)
 * )
 * assert.deepStrictEqual(
 *   pipe(
 *     O.none,
 *     E.fromOption(() => 'error')
 *   ),
 *   E.left('error')
 * )
 *
 * @category conversions
 * @since 2.0.0
 */
export var fromOption = 
/*#__PURE__*/ fromOption_(FromEither);
// -------------------------------------------------------------------------------------
// refinements
// -------------------------------------------------------------------------------------
/**
 * Returns `true` if the either is an instance of `Left`, `false` otherwise.
 *
 * @category refinements
 * @since 2.0.0
 */
export var isLeft = _.isLeft;
/**
 * Returns `true` if the either is an instance of `Right`, `false` otherwise.
 *
 * @category refinements
 * @since 2.0.0
 */
export var isRight = _.isRight;
/**
 * Less strict version of [`match`](#match).
 *
 * The `W` suffix (short for **W**idening) means that the handler return types will be merged.
 *
 * @category pattern matching
 * @since 2.10.0
 */
export var matchW = function (onLeft, onRight) {
    return function (ma) {
        return isLeft(ma) ? onLeft(ma.left) : onRight(ma.right);
    };
};
/**
 * Alias of [`matchW`](#matchw).
 *
 * @category pattern matching
 * @since 2.10.0
 */
export var foldW = matchW;
/**
 * Takes two functions and an `Either` value, if the value is a `Left` the inner value is applied to the first function,
 * if the value is a `Right` the inner value is applied to the second function.
 *
 * @example
 * import { match, left, right } from 'fp-ts/Either'
 * import { pipe } from 'fp-ts/function'
 *
 * function onLeft(errors: Array<string>): string {
 *   return `Errors: ${errors.join(', ')}`
 * }
 *
 * function onRight(value: number): string {
 *   return `Ok: ${value}`
 * }
 *
 * assert.strictEqual(
 *   pipe(
 *     right(1),
 *     match(onLeft, onRight)
 *   ),
 *   'Ok: 1'
 * )
 * assert.strictEqual(
 *   pipe(
 *     left(['error 1', 'error 2']),
 *     match(onLeft, onRight)
 *   ),
 *   'Errors: error 1, error 2'
 * )
 *
 * @category pattern matching
 * @since 2.10.0
 */
export var match = matchW;
/**
 * Alias of [`match`](#match).
 *
 * @category pattern matching
 * @since 2.0.0
 */
export var fold = match;
/**
 * Less strict version of [`getOrElse`](#getorelse).
 *
 * The `W` suffix (short for **W**idening) means that the handler return type will be merged.
 *
 * @category error handling
 * @since 2.6.0
 */
export var getOrElseW = function (onLeft) {
    return function (ma) {
        return isLeft(ma) ? onLeft(ma.left) : ma.right;
    };
};
/**
 * Returns the wrapped value if it's a `Right` or a default value if is a `Left`.
 *
 * @example
 * import { getOrElse, left, right } from 'fp-ts/Either'
 * import { pipe } from 'fp-ts/function'
 *
 * assert.deepStrictEqual(
 *   pipe(
 *     right(1),
 *     getOrElse(() => 0)
 *   ),
 *   1
 * )
 * assert.deepStrictEqual(
 *   pipe(
 *     left('error'),
 *     getOrElse(() => 0)
 *   ),
 *   0
 * )
 *
 * @category error handling
 * @since 2.0.0
 */
export var getOrElse = getOrElseW;
// -------------------------------------------------------------------------------------
// combinators
// -------------------------------------------------------------------------------------
/**
 * @category mapping
 * @since 2.10.0
 */
export var flap = /*#__PURE__*/ flap_(Functor);
/**
 * Combine two effectful actions, keeping only the result of the first.
 *
 * @since 2.0.0
 */
export var apFirst = /*#__PURE__*/ apFirst_(Apply);
/**
 * Less strict version of [`apFirst`](#apfirst)
 *
 * The `W` suffix (short for **W**idening) means that the error types will be merged.
 *
 * @since 2.12.0
 */
export var apFirstW = apFirst;
/**
 * Combine two effectful actions, keeping only the result of the second.
 *
 * @since 2.0.0
 */
export var apSecond = /*#__PURE__*/ apSecond_(Apply);
/**
 * Less strict version of [`apSecond`](#apsecond)
 *
 * The `W` suffix (short for **W**idening) means that the error types will be merged.
 *
 * @since 2.12.0
 */
export var apSecondW = apSecond;
/**
 * Composes computations in sequence, using the return value of one computation to determine the next computation and
 * keeping only the result of the first.
 *
 * @category sequencing
 * @since 2.0.0
 */
export var chainFirst = 
/*#__PURE__*/ chainFirst_(Chain);
/**
 * Less strict version of [`chainFirst`](#chainfirst)
 *
 * The `W` suffix (short for **W**idening) means that the error types will be merged.
 *
 * @category sequencing
 * @since 2.8.0
 */
export var chainFirstW = chainFirst;
/**
 * Less strict version of [`flatten`](#flatten).
 *
 * The `W` suffix (short for **W**idening) means that the error types will be merged.
 *
 * @category sequencing
 * @since 2.11.0
 */
export var flattenW = 
/*#__PURE__*/ chainW(identity);
/**
 * The `flatten` function is the conventional monad join operator. It is used to remove one level of monadic structure, projecting its bound argument into the outer level.
 *
 * @example
 * import * as E from 'fp-ts/Either'
 *
 * assert.deepStrictEqual(E.flatten(E.right(E.right('a'))), E.right('a'))
 * assert.deepStrictEqual(E.flatten(E.right(E.left('e'))), E.left('e'))
 * assert.deepStrictEqual(E.flatten(E.left('e')), E.left('e'))
 *
 * @category sequencing
 * @since 2.0.0
 */
export var flatten = flattenW;
/**
 * @since 2.0.0
 */
export var duplicate = /*#__PURE__*/ extend(identity);
/**
 * @category lifting
 * @since 2.10.0
 */
export var fromOptionK = 
/*#__PURE__*/ fromOptionK_(FromEither);
/**
 * @category sequencing
 * @since 2.11.0
 */
export var chainOptionK = /*#__PURE__*/ chainOptionK_(FromEither, Chain);
/**
 * @example
 * import * as E from 'fp-ts/Either'
 * import { pipe } from 'fp-ts/function'
 *
 * assert.deepStrictEqual(
 *   pipe(
 *     E.right(1),
 *     E.filterOrElse(
 *       (n) => n > 0,
 *       () => 'error'
 *     )
 *   ),
 *   E.right(1)
 * )
 * assert.deepStrictEqual(
 *   pipe(
 *     E.right(-1),
 *     E.filterOrElse(
 *       (n) => n > 0,
 *       () => 'error'
 *     )
 *   ),
 *   E.left('error')
 * )
 * assert.deepStrictEqual(
 *   pipe(
 *     E.left('a'),
 *     E.filterOrElse(
 *       (n) => n > 0,
 *       () => 'error'
 *     )
 *   ),
 *   E.left('a')
 * )
 *
 * @category filtering
 * @since 2.0.0
 */
export var filterOrElse = /*#__PURE__*/ filterOrElse_(FromEither, Chain);
/**
 * Less strict version of [`filterOrElse`](#filterorelse).
 *
 * The `W` suffix (short for **W**idening) means that the error types will be merged.
 *
 * @category filtering
 * @since 2.9.0
 */
export var filterOrElseW = filterOrElse;
/**
 * Returns a `Right` if is a `Left` (and vice versa).
 *
 * @since 2.0.0
 */
export var swap = function (ma) { return (isLeft(ma) ? right(ma.left) : left(ma.right)); };
/**
 * Less strict version of [`orElse`](#orelse).
 *
 * The `W` suffix (short for **W**idening) means that the return types will be merged.
 *
 * @category error handling
 * @since 2.10.0
 */
export var orElseW = function (onLeft) {
    return function (ma) {
        return isLeft(ma) ? onLeft(ma.left) : ma;
    };
};
/**
 * Useful for recovering from errors.
 *
 * @category error handling
 * @since 2.0.0
 */
export var orElse = orElseW;
/**
 * Takes a default and a nullable value, if the value is not nully, turn it into a `Right`, if the value is nully use
 * the provided default as a `Left`.
 *
 * @example
 * import { fromNullable, left, right } from 'fp-ts/Either'
 *
 * const parse = fromNullable('nully')
 *
 * assert.deepStrictEqual(parse(1), right(1))
 * assert.deepStrictEqual(parse(null), left('nully'))
 *
 * @category conversions
 * @since 2.0.0
 */
export var fromNullable = function (e) {
    return function (a) {
        return a == null ? left(e) : right(a);
    };
};
/**
 * Constructs a new `Either` from a function that might throw.
 *
 * See also [`tryCatchK`](#trycatchk).
 *
 * @example
 * import * as E from 'fp-ts/Either'
 *
 * const unsafeHead = <A>(as: ReadonlyArray<A>): A => {
 *   if (as.length > 0) {
 *     return as[0]
 *   } else {
 *     throw new Error('empty array')
 *   }
 * }
 *
 * const head = <A>(as: ReadonlyArray<A>): E.Either<Error, A> =>
 *   E.tryCatch(() => unsafeHead(as), e => (e instanceof Error ? e : new Error('unknown error')))
 *
 * assert.deepStrictEqual(head([]), E.left(new Error('empty array')))
 * assert.deepStrictEqual(head([1, 2, 3]), E.right(1))
 *
 * @category interop
 * @since 2.0.0
 */
export var tryCatch = function (f, onThrow) {
    try {
        return right(f());
    }
    catch (e) {
        return left(onThrow(e));
    }
};
/**
 * Converts a function that may throw to one returning a `Either`.
 *
 * @category interop
 * @since 2.10.0
 */
export var tryCatchK = function (f, onThrow) {
    return function () {
        var a = [];
        for (var _i = 0; _i < arguments.length; _i++) {
            a[_i] = arguments[_i];
        }
        return tryCatch(function () { return f.apply(void 0, a); }, onThrow);
    };
};
/**
 * @category lifting
 * @since 2.9.0
 */
export var fromNullableK = function (e) {
    var from = fromNullable(e);
    return function (f) { return flow(f, from); };
};
/**
 * @category sequencing
 * @since 2.9.0
 */
export var chainNullableK = function (e) {
    var from = fromNullableK(e);
    return function (f) { return chain(from(f)); };
};
/**
 * @category conversions
 * @since 2.10.0
 */
export var toUnion = /*#__PURE__*/ foldW(identity, identity);
// -------------------------------------------------------------------------------------
// utils
// -------------------------------------------------------------------------------------
/**
 * Default value for the `onError` argument of `tryCatch`
 *
 * @since 2.0.0
 */
export function toError(e) {
    return e instanceof Error ? e : new Error(String(e));
}
export function elem(E) {
    return function (a, ma) {
        if (ma === undefined) {
            var elemE_1 = elem(E);
            return function (ma) { return elemE_1(a, ma); };
        }
        return isLeft(ma) ? false : E.equals(a, ma.right);
    };
}
/**
 * Returns `false` if `Left` or returns the result of the application of the given predicate to the `Right` value.
 *
 * @example
 * import { exists, left, right } from 'fp-ts/Either'
 *
 * const gt2 = exists((n: number) => n > 2)
 *
 * assert.strictEqual(gt2(left('a')), false)
 * assert.strictEqual(gt2(right(1)), false)
 * assert.strictEqual(gt2(right(3)), true)
 *
 * @since 2.0.0
 */
export var exists = function (predicate) {
    return function (ma) {
        return isLeft(ma) ? false : predicate(ma.right);
    };
};
// -------------------------------------------------------------------------------------
// do notation
// -------------------------------------------------------------------------------------
/**
 * @category do notation
 * @since 2.9.0
 */
export var Do = /*#__PURE__*/ of(_.emptyRecord);
/**
 * @category do notation
 * @since 2.8.0
 */
export var bindTo = /*#__PURE__*/ bindTo_(Functor);
var let_ = /*#__PURE__*/ let__(Functor);
export { 
/**
 * @category do notation
 * @since 2.13.0
 */
let_ as let };
/**
 * @category do notation
 * @since 2.8.0
 */
export var bind = /*#__PURE__*/ bind_(Chain);
/**
 * The `W` suffix (short for **W**idening) means that the error types will be merged.
 *
 * @category do notation
 * @since 2.8.0
 */
export var bindW = bind;
/**
 * @category do notation
 * @since 2.8.0
 */
export var apS = /*#__PURE__*/ apS_(Apply);
/**
 * Less strict version of [`apS`](#aps).
 *
 * The `W` suffix (short for **W**idening) means that the error types will be merged.
 *
 * @category do notation
 * @since 2.8.0
 */
export var apSW = apS;
/**
 * @since 2.11.0
 */
export var ApT = /*#__PURE__*/ of(_.emptyReadonlyArray);
// -------------------------------------------------------------------------------------
// array utils
// -------------------------------------------------------------------------------------
/**
 * Equivalent to `ReadonlyNonEmptyArray#traverseWithIndex(Applicative)`.
 *
 * @category traversing
 * @since 2.11.0
 */
export var traverseReadonlyNonEmptyArrayWithIndex = function (f) {
    return function (as) {
        var e = f(0, _.head(as));
        if (isLeft(e)) {
            return e;
        }
        var out = [e.right];
        for (var i = 1; i < as.length; i++) {
            var e_1 = f(i, as[i]);
            if (isLeft(e_1)) {
                return e_1;
            }
            out.push(e_1.right);
        }
        return right(out);
    };
};
/**
 * Equivalent to `ReadonlyArray#traverseWithIndex(Applicative)`.
 *
 * @category traversing
 * @since 2.11.0
 */
export var traverseReadonlyArrayWithIndex = function (f) {
    var g = traverseReadonlyNonEmptyArrayWithIndex(f);
    return function (as) { return (_.isNonEmpty(as) ? g(as) : ApT); };
};
/**
 * Equivalent to `ReadonlyArray#traverseWithIndex(Applicative)`.
 *
 * @category traversing
 * @since 2.9.0
 */
export var traverseArrayWithIndex = traverseReadonlyArrayWithIndex;
/**
 * Equivalent to `ReadonlyArray#traverse(Applicative)`.
 *
 * @category traversing
 * @since 2.9.0
 */
export var traverseArray = function (f) { return traverseReadonlyArrayWithIndex(function (_, a) { return f(a); }); };
/**
 * Equivalent to `ReadonlyArray#sequence(Applicative)`.
 *
 * @category traversing
 * @since 2.9.0
 */
export var sequenceArray = 
/*#__PURE__*/ traverseArray(identity);
/**
 * Use [`parse`](./Json.ts.html#parse) instead.
 *
 * @category zone of death
 * @since 2.0.0
 * @deprecated
 */
export function parseJSON(s, onError) {
    return tryCatch(function () { return JSON.parse(s); }, onError);
}
/**
 * Use [`stringify`](./Json.ts.html#stringify) instead.
 *
 * @category zone of death
 * @since 2.0.0
 * @deprecated
 */
export var stringifyJSON = function (u, onError) {
    return tryCatch(function () {
        var s = JSON.stringify(u);
        if (typeof s !== 'string') {
            throw new Error('Converting unsupported structure to JSON');
        }
        return s;
    }, onError);
};
/**
 * This instance is deprecated, use small, specific instances instead.
 * For example if a function needs a `Functor` instance, pass `E.Functor` instead of `E.either`
 * (where `E` is from `import E from 'fp-ts/Either'`)
 *
 * @category zone of death
 * @since 2.0.0
 * @deprecated
 */
export var either = {
    URI: URI,
    map: _map,
    of: of,
    ap: _ap,
    chain: _chain,
    reduce: _reduce,
    foldMap: _foldMap,
    reduceRight: _reduceRight,
    traverse: _traverse,
    sequence: sequence,
    bimap: _bimap,
    mapLeft: _mapLeft,
    alt: _alt,
    extend: _extend,
    chainRec: _chainRec,
    throwError: throwError
};
/**
 * Use [`getApplySemigroup`](./Apply.ts.html#getapplysemigroup) instead.
 *
 * Semigroup returning the left-most `Left` value. If both operands are `Right`s then the inner values
 * are concatenated using the provided `Semigroup`
 *
 * @category zone of death
 * @since 2.0.0
 * @deprecated
 */
export var getApplySemigroup = 
/*#__PURE__*/ getApplySemigroup_(Apply);
/**
 * Use [`getApplicativeMonoid`](./Applicative.ts.html#getapplicativemonoid) instead.
 *
 * @category zone of death
 * @since 2.0.0
 * @deprecated
 */
export var getApplyMonoid = 
/*#__PURE__*/ getApplicativeMonoid(Applicative);
/**
 * Use [`getApplySemigroup`](./Apply.ts.html#getapplysemigroup) instead.
 *
 * @category zone of death
 * @since 2.0.0
 * @deprecated
 */
export var getValidationSemigroup = function (SE, SA) {
    return getApplySemigroup_(getApplicativeValidation(SE))(SA);
};
/**
 * Use [`getApplicativeMonoid`](./Applicative.ts.html#getapplicativemonoid) instead.
 *
 * @category zone of death
 * @since 2.0.0
 * @deprecated
 */
export var getValidationMonoid = function (SE, MA) {
    return getApplicativeMonoid(getApplicativeValidation(SE))(MA);
};
/**
 * Use [`getApplicativeValidation`](#getapplicativevalidation) and [`getAltValidation`](#getaltvalidation) instead.
 *
 * @category zone of death
 * @since 2.0.0
 * @deprecated
 */
export function getValidation(SE) {
    var ap = getApplicativeValidation(SE).ap;
    var alt = getAltValidation(SE).alt;
    return {
        URI: URI,
        _E: undefined,
        map: _map,
        of: of,
        chain: _chain,
        bimap: _bimap,
        mapLeft: _mapLeft,
        reduce: _reduce,
        foldMap: _foldMap,
        reduceRight: _reduceRight,
        extend: _extend,
        traverse: _traverse,
        sequence: sequence,
        chainRec: _chainRec,
        throwError: throwError,
        ap: ap,
        alt: alt
    };
}