swiftstringexpression-evaluation

Can you evaluate a string in Swift?


I have a variable and I have a function stored in it as a string:

var x = "func myFunction(y :Int) {println(y)}"

Is there a way to evaluate the string and run the function?


Solution

  • No.

    There is no equivalent of eval() in JavaScript or ScriptEngine in Java for Swift.

    A common use for string evaluation is mathematical expressions; if you want to evaluate these, you can use NSExpression.valueWithExpression(format: String):

    let stringWithMathematicalOperation: String = "5*5" // Example
    let exp: NSExpression = NSExpression(format: stringWithMathematicalOperation)
    let result: Double = exp.expressionValue(with:nil, context: nil) as! Double // 25.0