content: /* 
   * Kodkod -- Copyright (c) 2005-present, Emina Torlak
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   */
  package kodkod.ast;
  
  
  import kodkod.ast.operator.IntOperator;
  import kodkod.ast.visitor.ReturnVisitor;
  import kodkod.ast.visitor.VoidVisitor;
  
  /**
   * A binary integer expression such as x + y.
   * @specfield left: IntExpression
   * @specfield right: IntExpression
   * @specfield op: IntOperator
   * @specfield op.binary()
   * @invariant children = 0->left + 1->right
   * @author Emina Torlak
   */
  public final class BinaryIntExpression extends IntExpression  {
  	private final IntOperator op;
  	private final IntExpression left, right;
  	
  	/**  
  	 * Constructs a new binary int formula: left op right
  	 * 
  	 * @ensures this.left' = left && this.right' = right && this.op' = op
  	 * @throws NullPointerException  left = null || right = null || op = null
  	 */
  	public BinaryIntExpression(final IntExpression left, final IntOperator op, final IntExpression right) {
  		if (!op.binary()) throw new IllegalArgumentException("Not a binary operator: " + op);
  		this.left = left;
  		this.right = right;
  		this.op = op;
  	}
  
  	/**
  	 * Returns the left child of this.
  	 * @return this.left
  	 */
  	public IntExpression left() {return left;}
  	
  	/**
  	 * Returns the right child of this.
  	 * @return this.right
  	 */
  	public IntExpression right() {return right;}
  	
  	/**
  	 * Returns the operator of this.
  	 * @return this.op
  	 */
  	public IntOperator op() {return op;}
  	
  	/**
  	 * {@inheritDoc}
  	 * @see kodkod.ast.IntExpression#accept(kodkod.ast.visitor.ReturnVisitor)
  	 */
  	@Override
  	public <E, F, D, I> I accept(ReturnVisitor<E, F, D, I> visitor) {
  		return visitor.visit(this);
  	}
  
  	/**
  	 * {@inheritDoc}
  	 * @see kodkod.ast.IntExpression#accept(kodkod.ast.visitor.VoidVisitor)
  	 */
  	@Override
  	public void accept(VoidVisitor visitor) {
  		visitor.visit(this);
  	}
  
  	/**
       * {@inheritDoc}
       * @see kodkod.ast.Node#toString()
       */
  	public String toString() {
  		return "(" + left + " " + op + " " + right + ")";
  	}
  }
  