public class Sub extends ArithBinary {
  public Sub (int id) {
  }
  public Object sem () throws SemanticException {
    return super.sem("-");
  }
  public Object run () {
    if (T == Integer.class)
      return IntLit.sub((Number)a.run(), (Number)b.run());
    return FloatLit.sub((Number)a.run(), (Number)b.run());
  }
}