39 lines
1.4 KiB
JavaScript
39 lines
1.4 KiB
JavaScript
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"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.getAlternativeMonoid = exports.altAll = void 0;
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/**
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* The `Alternative` type class extends the `Alt` type class with a value that should be the left and right identity for `alt`.
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*
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* It is similar to `Monoid`, except that it applies to types of kind `* -> *`, like `Array` or `Option`, rather than
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* concrete types like `string` or `number`.
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*
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* `Alternative` instances should satisfy the following laws:
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*
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* 1. Left identity: `A.alt(zero, fa) <-> fa`
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* 2. Right identity: `A.alt(fa, zero) <-> fa`
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* 3. Annihilation: `A.map(zero, f) <-> zero`
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* 4. Distributivity: `A.ap(A.alt(fab, gab), fa) <-> A.alt(A.ap(fab, fa), A.ap(gab, fa))`
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* 5. Annihilation: `A.ap(zero, fa) <-> zero`
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*
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* @since 2.0.0
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*/
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var Alt_1 = require("./Alt");
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var Apply_1 = require("./Apply");
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function altAll(F) {
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return (0, Alt_1.altAll)(F)(F.zero());
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}
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exports.altAll = altAll;
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function getAlternativeMonoid(F) {
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var f = (0, Apply_1.getApplySemigroup)(F);
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return function (S) {
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var SF = f(S);
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return {
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concat: function (first, second) {
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return F.alt(SF.concat(first, second), function () { return F.alt(first, function () { return second; }); });
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},
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empty: F.zero()
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};
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};
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}
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exports.getAlternativeMonoid = getAlternativeMonoid;
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