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 java.util.Iterator;
  
  import kodkod.ast.operator.IntOperator;
  import kodkod.ast.visitor.ReturnVisitor;
  import kodkod.ast.visitor.VoidVisitor;
  import kodkod.util.collections.Containers;
  
  /**
   * A {@linkplain kodkod.ast.IntExpression int expression} with more than two children,
   * composed with an nary {@linkplain IntOperator operator}.
   * 
   * @specfield op: IntOperator
   * @invariant op.nary()
   * @invariant #children > 2
   * @author Emina Torlak 
   */
  public final class NaryIntExpression extends IntExpression implements Iterable<IntExpression> {
  
  	private final IntOperator op;
  	private final IntExpression[] children;
  	
  	/**  
  	 * Constructs a new composite IntExpression: op(children)
  	 * @requires children array is not modified while in use by this composite IntExpression
  	 * @requires some op.op[children]
  	 * @ensures this.children' = children && this.op' = op
  	 */
  	NaryIntExpression(IntOperator op, IntExpression[] children) { 
  		assert children.length>2;
  		if (!op.nary()) 
  			throw new IllegalArgumentException("Cannot construct an nary int expression using the non-nary operator " + op);
  		this.op = op;
  		this.children = children;
  	}
  
  	/**
       * Returns the operator of this.
       * @return this.op
       */
      public IntOperator op() {return op;}
      
  	/**
  	 * Returns the number of children of this int expression.
  	 * @return #this.children
  	 */
  	public int size() { return children.length; }
  	
  	/**
  	 * Returns the ith child of this int expression.
  	 * @requires 0 <= i < #this.children
  	 * @return this.children[i]
  	 */
  	public IntExpression child(int i) { return children[i]; }
  	
  	/**
  	 * Returns an iterator over this int expression's children,
  	 * in the increasing order of indices.
  	 * @return an iterator over this int expression's children,
  	 * in the increasing order of indices.
  	 */
  	public Iterator<IntExpression> iterator() { return Containers.iterate(children); }
      
  
  	/**
  	 * {@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()
  	 */
  	@Override
  	public String toString() {
  		final StringBuilder s = new StringBuilder("(");
  		s.append(child(0));
  		for(int i = 1, size = size(); i < size; i++) { 
  			s.append(" ");
  			s.append(op);
  			s.append(" ");
  			s.append(child(i));
  		}
  		s.append(")");
  		return s.toString();
  	}
  
  }
  