28 lines
1.1 KiB
JavaScript
28 lines
1.1 KiB
JavaScript
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/**
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* A `FunctorWithIndex` is a type constructor which supports a mapping operation `mapWithIndex`.
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*
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* `mapWithIndex` can be used to turn functions `i -> a -> b` into functions `f a -> f b` whose argument and return types use the type
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* constructor `f` to represent some computational context.
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*
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* Instances must satisfy the following laws:
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*
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* 1. Identity: `F.mapWithIndex(fa, (_i, a) => a) <-> fa`
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* 2. Composition: `F.mapWithIndex(fa, (_i, a) => bc(ab(a))) <-> F.mapWithIndex(F.mapWithIndex(fa, ab), bc)`
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*
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* @since 2.0.0
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*/
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import { pipe } from './function';
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import { getFunctorComposition } from './Functor';
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export function mapWithIndex(F, G) {
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return function (f) { return function (fa) { return F.mapWithIndex(fa, function (i, ga) { return G.mapWithIndex(ga, function (j, a) { return f([i, j], a); }); }); }; };
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}
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/** @deprecated */
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export function getFunctorWithIndexComposition(F, G) {
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var map = getFunctorComposition(F, G).map;
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var _mapWithIndex = mapWithIndex(F, G);
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return {
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map: map,
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mapWithIndex: function (fga, f) { return pipe(fga, _mapWithIndex(f)); }
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};
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}
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