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WIP: feat(core): Add utilities for natural numbers #10

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WIP: feat(core): Add utilities for natural numbers #10

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Binary file added .yarn/cache/typescript-npm-4.1.0-dev.20200908-7453357953-31c241fe35.zip
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2 changes: 2 additions & 0 deletions packages/core/src/common.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -69,3 +69,5 @@ export type Wrap<T, Box extends BoxType> = (
Box extends Set<any> ? Set<T> :
never
);

export type $FixMe = any;
12 changes: 12 additions & 0 deletions packages/core/src/natural.ts
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Original file line number Diff line number Diff line change
@@ -0,0 +1,12 @@
import type { $FixMe } from './common';
import type { TupleOf } from './tuple';

// Borrowed from https://twitter.com/danvdk/status/1302978402132074498
export type Add<A extends number, B extends number> = [...TupleOf<unknown, A>, ...TupleOf<unknown, B>]['length'] & number;

export type SubOne<N extends number> = TupleOf<unknown, N> extends [any, ...infer Tail] ? Tail['length'] : never;
export type Sub<A extends number, B extends number> = B extends 0 ? A : Sub<SubOne<A>, SubOne<B>>;

export type Mul<A extends number, B extends number, Result extends number = 0> = B extends 0 ? Result : Mul<A, SubOne<B>, Add<Result, A>>;

export type Mod<A extends number, B extends number> = $FixMe;
14 changes: 10 additions & 4 deletions packages/core/src/tuple.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -83,9 +83,9 @@ export type TupleMapUnwrap<
> = {
0: Result,
1: TupleMapUnwrap<
$Experimental.TupleTail<Tuple>,
TupleAppend<Result, Unwrap<$Experimental.TupleHead<Tuple>>>
>,
$Experimental.TupleTail<Tuple>,
TupleAppend<Result, Unwrap<$Experimental.TupleHead<Tuple>>>
>,
}[Tuple['length'] extends 0 ? 0 : 1];

export type TupleMapWrap<
Expand All @@ -98,11 +98,17 @@ export type TupleMapWrap<
$Experimental.TupleTail<Tuple>,
Box,
TupleAppend<Result, Wrap<$Experimental.TupleHead<Tuple>, Box>>
>,
>,
}[Tuple['length'] extends 0 ? 0 : 1];

// Borrowed from https://github.com/microsoft/TypeScript/pull/40002#issue-466243948
export type TupleOf<T, N extends number> = N extends N ? number extends N ? T[] : _TupleOf<T, N> : never;
export type _TupleOf<T, N extends number> = MakeTuple<T, N>;

// Credits to [Gal Schlezinger](https://github.com/schniz)
// See https://twitter.com/galstar/status/1299265344226439169
//
// @deprecated favor of TupleOf<T, N>
export type MakeTuple<T, N extends number, Result extends readonly T[] = []> = {
0: Result,
1: MakeTuple<T, N, [T, ...Result]>,
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