maps a range of input to a range of output

mapping.swift

import Cocoa

var str = "Hello, playground"

typealias LinearEquation = Double -> Double

func getLinearEquation(inp: (min: Double, max: Double),
         out: (min: Double, max: Double)) -> LinearEquation {
    
    let m = (out.max - out.min) / (inp.max - inp.min)
    let b = out.max - m * inp.max
    return {
        $0 * m + b
    }
}


let linearmap = getLinearEquation((3, 5), out: (20, 60))

linearmap(3)
linearmap(5)