typocomath/src/numbers/arithmetic.ts

48 lines
2.2 KiB
TypeScript

import {configDependency} from '../core/Config.js'
import {Signature, Dependency, ImpType} from '../core/Dispatcher.js'
import type {Complex} from '../Complex/type.js'
declare module "./type" {
interface NumbersReturn<Params> {
// This description loses information: some subtypes like NumInt or
// Positive are closed under addition, but this says that the result
// of add is just a number, not still of the reduced type
add: Signature<Params, [number, number], number>
// Whereas this one would preserve information, but would lie
// because it claims all subtypes of number are closed under addition,
// which is not true for `1 | 2 | 3`, for example.
// add: Params extends BBinary<infer B>
// ? B extends number ? B : never
// : never
//
// Not sure how this will need to go when we introduce NumInt.
unaryMinus: Signature<Params, [number], number>
subtract: Signature<Params, [number, number], number>
multiply: Signature<Params, [number, number], number>
divide: Signature<Params, [number, number], number>
// Best we can do for sqrt at compile time, since actual return
// type depends on config. Not sure how this will play out
// when we make a number-only bundle, but at least the import type
// above for Complex<> does not lead to any emitted JavaScript.
sqrt: Signature<Params, [number], number | Complex<number>>
}
}
export const add: ImpType<'add', [number, number]> = (a, b) => a + b
export const unaryMinus: ImpType<'unaryMinus', [number]> = a => -a
export const subtract: ImpType<'subtract', [number, number]> = (a, b) => a - b
export const multiply: ImpType<'multiply', [number, number]> = (a, b) => a * b
export const divide: ImpType<'divide', [number, number]> = (a, b) => a / b
export const sqrt =
(dep: configDependency
& Dependency<'complex', [number, number]>): ImpType<'sqrt', [number]> => {
if (dep.config.predictable || !dep.complex) {
return a => isNaN(a) ? NaN : Math.sqrt(a)
}
return a => {
if (isNaN(a)) return NaN
if (a >= 0) return Math.sqrt(a)
return dep.complex(0, Math.sqrt(unaryMinus(a)))
}
}