/** Our internal representation of a Ifnz
 * in the S0 language.
 * See http://www.radford.edu/itec380/2017fall-ibarland/Project
 * 
 * @author Ian Barland
 * @version 2016.Nov.09
 */
public class Ifnz extends Expr {
  static final String TOKEN = "(";
  
  Expr cond, nzBranch, zBranch;
  
  Ifnz( Expr _cond, Expr _nzBranch, Expr _zBranch) {
    this.cond = _cond;
    this.nzBranch = _nzBranch;
    this.zBranch = _zBranch;
    }
  
  public String toString() {
    return TOKEN
         + this.cond.toString()
         + ") !0 "
         + this.nzBranch.toString()
         + " : "
         + this.zBranch.toString()
         ;
    }
    
  static final double EPSILON = 1e-10;
  public Value eval() {
    if (!(Math.abs(((Num)(cond.eval())).doubleValue()) < EPSILON)) {
      return this.nzBranch.eval();
      }
   else {
      return this.zBranch.eval();
      }
    }
    
  @Override
  public boolean equals( /* Ifnz this, */ Object that) {
    if (this==that) {
      return true;
      }
    else if (that==null) {
      return false;
      }
   else if (this.getClass() != that.getClass()) {
      return false;
      }
   else {
      Ifnz thatt = (Ifnz) that;
      return this.cond.equals(thatt.cond)
          && this.nzBranch.equals(thatt.nzBranch)
          && this.zBranch.equals(thatt.zBranch);
      }
    
    }
    
  @Override
  public int hashCode() {
    if (cachedHash == null) {
      int hashSoFar = (int)0x314d2ef361bcd159L; // fingerprint
      hashSoFar += this.cond.hashCode();
      hashSoFar *= 31;
      hashSoFar += this.nzBranch.hashCode();
      hashSoFar *= 31;
      hashSoFar += this.zBranch.hashCode();
      cachedHash = hashSoFar;
      }
    return cachedHash;
    }
  private Integer cachedHash = null; 
  }