A Swift Playground for payroll. I have my reasons ...

payroll playground 1

// Swift playground experimenting with payroll.
// (I have my reasons.)

println("Hello")

import Foundation
// This stuff sets rounding to two places after decimal

var mode = NSRoundingMode.RoundPlain

var handler = NSDecimalNumberHandler(
    roundingMode: mode,
    scale: 2,
    raiseOnExactness: true,
    raiseOnOverflow: true,
    raiseOnUnderflow: true,
    raiseOnDivideByZero: true)

NSDecimalNumber.setDefaultBehavior(handler)

// rounding function saved for reference
// no longer necessary now that I've set default, 
// might come in handy for other than two digit rounding

func round(n: NSDecimalNumber) -> NSDecimalNumber {
    return n.decimalNumberByRoundingAccordingToBehavior(handler)
}

// operator extensions for convenient decimal

func dec(n: Double) -> NSDecimalNumber {
    return NSDecimalNumber(double: n)
}

@infix func +(left: NSDecimalNumber, right: NSDecimalNumber) -> NSDecimalNumber {
    return left.decimalNumberByAdding(right)
}

@infix func -(left: NSDecimalNumber, right: NSDecimalNumber) -> NSDecimalNumber {
    return left.decimalNumberBySubtracting(right)
}

@infix func /(left: NSDecimalNumber, right: NSDecimalNumber) -> NSDecimalNumber {
    return left.decimalNumberByDividingBy(right)
}

@infix func *(left: NSDecimalNumber, right: NSDecimalNumber) -> NSDecimalNumber {
    return left.decimalNumberByMultiplyingBy(right)
}

// useful constants

let twelve  = dec(12.0)
let taxRate = dec(0.25)
let zero    = dec(0)


// classes

class Person {
    let name: String
    let payRate: NSDecimalNumber
    
    init (name: String, rate: Double) {
        self.name = name
        payRate = dec(rate)
    }
}

class PayStub {
    let person: Person
    var salary = zero
    var grossPay = zero
    var fedTax = zero
    var deductions = zero
    var netPay = zero
    
    init(person: Person) {
        self.person = person
    }
    
    func pay() {
        salary     = person.payRate / twelve
        grossPay   = zero
        grossPay   = grossPay + salary
        fedTax     = grossPay * taxRate
        deductions = zero
        deductions = deductions + fedTax
        netPay     = grossPay - deductions
    }
}

var person = Person(name: "Jones", rate: 50000)
var jones = person
var smith = Person(name: "Smith", rate: 30000)

var stub = PayStub(person: person)
stub.pay()
stub.person.name
stub.salary
stub.grossPay
stub.fedTax
stub.deductions
stub.netPay

/*var inc = dec(0.01)
var tot = zero
for i in (0..100) {
    tot = tot + inc
}
tot
tot == dec(1.0)*/

// how to find the comma, god save me

var test = "123, Jones"
var j = test.rangeOfString(",")
var s = j.startIndex
var e = j.endIndex
test[s...e]

// maybe for our purposes we can just keep data in arrays

var jonesrecord = [1, "jones"]
var smithrecord = [2, "smith"]

// or dictionaries. yeah, that's it, dictionaries

var personnel = [1: jones, 2: smith]
personnel[2] // returns Person smith

Awesome stuff. Thanks