59 lines
1.5 KiB
TypeScript
59 lines
1.5 KiB
TypeScript
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/**
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* A `Magma` is a pair `(A, concat)` in which `A` is a non-empty set and `concat` is a binary operation on `A`
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*
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* See [Semigroup](https://gcanti.github.io/fp-ts/modules/Semigroup.ts.html) for some instances.
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*
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* @since 2.0.0
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*/
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import { Endomorphism } from './Endomorphism'
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import { Predicate } from './Predicate'
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/**
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* @category model
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* @since 2.0.0
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*/
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export interface Magma<A> {
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readonly concat: (x: A, y: A) => A
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}
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/**
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* The dual of a `Magma`, obtained by swapping the arguments of `concat`.
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*
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* @example
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* import { reverse, concatAll } from 'fp-ts/Magma'
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* import * as N from 'fp-ts/number'
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*
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* const subAll = concatAll(reverse(N.MagmaSub))(0)
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*
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* assert.deepStrictEqual(subAll([1, 2, 3]), 2)
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*
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* @since 2.11.0
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*/
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export declare const reverse: <A>(M: Magma<A>) => Magma<A>
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/**
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* @since 2.11.0
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*/
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export declare const filterFirst: <A>(predicate: Predicate<A>) => (M: Magma<A>) => Magma<A>
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/**
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* @since 2.11.0
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*/
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export declare const filterSecond: <A>(predicate: Predicate<A>) => (M: Magma<A>) => Magma<A>
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/**
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* @since 2.11.0
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*/
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export declare const endo: <A>(f: Endomorphism<A>) => (M: Magma<A>) => Magma<A>
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/**
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* Given a sequence of `as`, concat them and return the total.
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*
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* If `as` is empty, return the provided `startWith` value.
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*
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* @example
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* import { concatAll } from 'fp-ts/Magma'
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* import * as N from 'fp-ts/number'
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*
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* const subAll = concatAll(N.MagmaSub)(0)
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*
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* assert.deepStrictEqual(subAll([1, 2, 3]), -6)
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*
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* @since 2.11.0
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*/
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export declare const concatAll: <A>(M: Magma<A>) => (startWith: A) => (as: readonly A[]) => A
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