Arithmetic-Expression.playground

//: Playground - noun: a place where people can play

import Foundation
import UIKit

//As reference:
//https://spin.atomicobject.com/2015/03/24/evaluate-string-expressions-ios-objective-c-swift/

/**
 NSExpression
 */

let b = "3+3"
let c = "2+5+10*2+2/2*2/1+2+4"

//let c1 = 2+5+10*2+2/2*2/1+2+4

let exp = NSExpression(format: c)
let v = exp.expressionValue(with: nil, context: nil) as! NSNumber
print(#line, "dbg-v]:", v)


var logicalExpression = "1 + 2 > 2 || 4 - 2 = 0"
let predicate = NSPredicate(format: logicalExpression)
var result = predicate.evaluate(with:"") as Bool

print(#line, "dbg-result]:", result)


var numericExpression = "sqrt(4 + 2 - 2)" // + log(5)"
let expression = NSExpression(format: numericExpression)
var resultN = expression.expressionValue(with:nil, context: nil) as! NSNumber

print(#line, "dbg-resultN]:", resultN)



public extension NSNumber {
    func squareAndSubtractFive() -> NSNumber {
        return NSNumber(value: (self.doubleValue * self.doubleValue) - 5 )
    }
}

var stringExpression = "function(5, 'squareAndSubtractFive')"
let expressionE = NSExpression(format: stringExpression)
var resultE = expressionE.expressionValue(with:nil, context: nil) as! NSNumber

print(#line, "dbg-resultE]:", resultE)