WIP: TypeScriptの型システムで行列乗算の安全性を保証する

code:ts

type Append<Elm, T extends unknown[]> = ((

arg: Elm,

...rest: T

) => void) extends ((...args: infer T2) => void)

? T2

: never;

type Vector<N extends number, T> = VectorRec<N, T, [], []>;

type VectorRec<Num, Elm, T extends unknown[], C extends unknown[]> = {

0: T;

1: VectorRec<Num, Elm, Append<Elm, T>, Append<unknown, C>>;

type Matrix<N extends number, M extends number, T> = Vector<N, Vector<M, T>>;

// Type-safe matrix multiplecation

function matmul<N extends number, M extends number, L extends number, T>

(mat1: Matrix<N, M, T>, mat2: Matrix<M, L, T>): Matrix<N, L, T> {

return null as any; // TODO: implement

}

const mat1: Matrix<2, 3, number> = [

];

const mat2: Matrix<3, 4, number> = [

];

WIP

matmulの実装

TODO: このページが完成することがあるなら元Qiita記事の恩恵が大きいので追加