title: How to parse a calculator input string
body: <p>I'm writing a calculator, and when the user hits enter, I need it to find anywhere that there are parentheses for example.</p>
  
  <p>Then I need the calculator to solve the math inside those first.</p>
  
  <p>What would be the best way to get the functions inside the parentheses and set the value of a second <code>String</code> as whatever is inside the parentheses? </p>