simple AST handling example

enum AST
{
  Number(n:Float);
  Sum(n1:AST, n2:AST);
  Mult(n1:AST, n2:AST);
}

class ASTTools
{
  public static function execute(a:AST)
  {
    return switch(a)
    {
      case Number(n): n;
      case Sum(n1, n2): execute(n1) + execute(n2);
      case Mult(n1, n2): execute(n1) * execute(n2);
    }
  }
}

class Main
{
  static function main()
  {
    trace(ASTTools.execute( Sum( Mult(Number(20), Number(2)), Number(2) ) ));
  }
}