math5/src/numbers/arithmetic.ts

import {implementations} from '@/core/Dispatcher'
import type {CommonSignature} from '@/interfaces/type'

const conservativeSqrt = (a: number) => isNaN(a) ? NaN : Math.sqrt(a)

export const common = implementations<CommonSignature<number>>()
   .independent({
      add:       (a, b) => a + b,
      unaryMinus: a     => -a,
      subtract:  (a, b) => a - b,
      multiply:  (a, b) => a * b,
      absquare:   a     => a * a,
      reciprocal: a     => 1 / a,
      divide:    (a, b) => a / b,
      conj:       a     => a,
      conservativeSqrt })
   .dependent({config: {}, complex: {}}, {
      sqrt: dep => {
         if (dep.config().predictable || !dep.complex) return conservativeSqrt
         return a => {
            if (isNaN(a)) return NaN
            if (a >= 0) return Math.sqrt(a)
            return dep.complex(0, Math.sqrt(-a))
         }
      }})
   .ship()