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import { assertIsDefined, assertIsEquivalent, assertIsNone } from "./asserts.js";import { factorizeSumType } from "./SumType.js";
const $$value = Symbol.for("TypeValue");
export const Either = factorizeSumType(  "Either",  {    Left: [ $$value ],    Right: [ $$value ]  });
Either.fromNullable = value =>  !assertIsDefined(value) || assertIsNone(value) ? Either.Left(value) : Either.Right(value);Either.left = value => Either.Left(value);Either.right = value => Either.Right(value);Either.of = value => Either.Right(value);
// alt :: Either a b ~> Either a b -> Either a bEither.prototype.alt = Either.prototype["fantasy-land/alt"] = function (container) {
  return this.fold({    Left: _ => container,    Right: _ => this  });};
// ap :: Either a b ~> Either a (b -> c) -> Either a cEither.prototype.ap = function (container) {  if (Either.Left.is(this)) return (Either.Left.is(container)) ? container : this;
  return container.fold({    Left: _ => container,    Right: _ => Either.of(container[$$value](this[$$value]))  });};
// map :: Either a b ~> (b -> c) -> Either a cEither.prototype.map = function (composedFunction) {
  return this.fold({    Left: _ => this,    Right: _ => Either.of(composedFunction(this[$$value]))  });};
// chain :: Either a b ~> (b -> Either a c) -> Either a cEither.prototype.chain = function (composedFunction) {
  return this.fold({    Left: _ => this,    Right: _ => composedFunction(this[$$value])  });};
Deno.test(  "Either: #right",  () =>    assertIsEquivalent(Either.right(42), Either.Right(42)));
Deno.test(  "Either.Right: #alt",  () =>    assertIsEquivalent(      Either.Right(42).alt(Either.Right(24)),      Either.Right(42)    ));
Deno.test(  "Either.Right: #ap - Composition",  () => {    const containerA = Either.Right(42);    const containerB = Either.Right(x => x + 2);    const containerC = Either.Right(x => x * 2);
    assertIsEquivalent(      containerA.ap(containerB.ap(containerC.map(a => b => c => a(b(c))))),      containerA.ap(containerB).ap(containerC)    );  });
Deno.test(  "Either.Right: #chain",  () =>    assertIsEquivalent(      Either.Right(42).chain(x => Either.of(x * 2)),      Either.Right(84)    ));
Deno.test(  "Either.Right: #map",  () =>    assertIsEquivalent(      Either.Right(42).map(x => x * 2),      Either.Right(84)    ));
Deno.test(  "Either.Right: #map - Identity",  () => {    const container = Either.Right(42);
    assertIsEquivalent(      container.map(x => x),      container    );  });
Deno.test(  "Either.Right: #map - Composition",  () => {    const container = Either.Right(42);    const f = x => x + 2;    const g = x => x * 2;
    assertIsEquivalent(      container.map(f).map(g),      container.map(x => g(f(x)))    );  });
Deno.test(  "Either.Left: #alt",  () =>    assertIsEquivalent(      Either.Left(32).alt(Either.Right(42)),      Either.Right(42)    ));
Deno.test(  "Either.Left: #map",  () =>    assertIsEquivalent(      Either.Left(32).map(x => x * 2),      Either.Left(32)    ));
Deno.test(  "Either.Left: #map - Identity",  () => {    const container = Either.Left(32);
    assertIsEquivalent(      container.map(x => x),      container    );  });
Deno.test(  "Either.Left: #map - Composition",  () => {    const container = Either.Left(32);    const f = x => x + 2;    const g = x => x * 2;
    assertIsEquivalent(      container.map(f).map(g),      container.map(x => g(f(x)))    );  });
export default Either;