Simple Command Line Calculator

CommandLineCalc.swift

//
//  main.swift
//  Calculator
//
//  Created by NeilsUltimateLab on 03/06/18.
//  Copyright © 2018 NeilsUltimateLab. All rights reserved.
//

import Foundation

enum Token {
    case sqrt(Float)
    case sum(Float, Float)
    case minus(Float, Float)
    case multi(Float, Float)
    case div(Float, Float)
    
    private enum Command: String {
        case sqrt
        case sum
        case minus
        case multi
        case div
    }
    
    init?(rawValue: Array<String>) {
        guard !rawValue.isEmpty else { return nil }
        if let command = Command(rawValue: rawValue[0]) {
            switch command {
            case .sqrt:
                guard let value = Float(rawValue[1]) else { return nil }
                self = .sqrt(value)
            case .sum:
                guard let val1 = Float(rawValue[1]), let val2 = Float(rawValue[2]) else { return nil }
                self = .sum(val1, val2)
            case .minus:
                guard let val1 = Float(rawValue[1]), let val2 = Float(rawValue[2]) else { return nil }
                self = .minus(val1, val2)
            case .multi:
                guard let val1 = Float(rawValue[1]), let val2 = Float(rawValue[2]) else { return nil }
                self = .multi(val1, val2)
            case .div:
                guard let val1 = Float(rawValue[1]), let val2 = Float(rawValue[2]) else { return nil }
                self = .div(val1, val2)
            }
            return
        }
        return nil
    }
}

func compute(for token: Token) {
    switch token {
    case .sqrt(let val):
        print("\nThe square root is: ", sqrt(Double(val)), "\n")
    case .sum(let val1, let val2):
        print("\nThe addition result is: ", val1 + val2, "\n")
    case let .minus(val1, val2):
        print("\nThe negation result is: ", val1 + val2, "\n")
    case let .div(val1, val2):
        guard val2 > 0 else {
            print("\nWow you got an \"Infinity\"\n")
            return
        }
        print("\nThe division result is: ", val1/val2, "\n")
    case let .multi(val1, val2):
        print("\nThe multiplication result is: ", val1 * val2, "\n")
    }
}

func parse(input: Array<String>) {
    if let token = Token(rawValue: input) {
        compute(for: token)
    }
}

func main() {
    let argumanets = CommandLine.arguments.dropFirst()
    parse(input: Array(argumanets))
}

main()