/*****************************************************************************
 * Licensed to the Apache Software Foundation (ASF) under one                *
 * or more contributor license agreements.  See the NOTICE file              *
 * distributed with this work for additional information                     *
 * regarding copyright ownership.  The ASF licenses this file                *
 * to you under the Apache License, Version 2.0 (the                         *
 * "License"); you may not use this file except in compliance                *
 * with the License.  You may obtain a copy of the License at                *
 *                                                                           *
 *     http://www.apache.org/licenses/LICENSE-2.0                            *
 *                                                                           *
 * Unless required by applicable law or agreed to in writing,                *
 * software distributed under the License is distributed on an               *
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY                    *
 * KIND, either express or implied.  See the License for the                 *
 * specific language governing permissions and limitations                   *
 * under the License.                                                        *
 *                                                                           *
 * This file is part of the BeanShell Java Scripting distribution.           *
 * Documentation and updates may be found at http://www.beanshell.org/       *
 * Patrick Niemeyer (pat@pat.net)                                            *
 * Author of Learning Java, O'Reilly & Associates                            *
 *                                                                           *
 *****************************************************************************/

package bsh;

/**
 * This class handles both {@code while} statements and {@code do..while} statements.
*/
class BSHWhileStatement extends SimpleNode implements ParserConstants {

	/**
	 * Set by Parser, default {@code false}
	 */
	boolean isDoStatement;

    BSHWhileStatement(int id) {
		super(id);
	}


    public Object eval( CallStack callstack, Interpreter interpreter) throws EvalError {
		int numChild = jjtGetNumChildren();

		// Order of body and condition is swapped for do / while
        final SimpleNode condExp;
		final SimpleNode body;

		if ( isDoStatement ) {
			condExp = (SimpleNode) jjtGetChild(1);
			body = (SimpleNode) jjtGetChild(0);
		} else {
			condExp = (SimpleNode) jjtGetChild(0);
			if ( numChild > 1 )	{
				body = (SimpleNode) jjtGetChild(1);
			} else {
				body = null;
			}
		}

		boolean doOnceFlag = isDoStatement;

        while (doOnceFlag || BSHIfStatement.evaluateCondition(condExp, callstack, interpreter)) {
			doOnceFlag = false;
			// no body?
			if ( body == null ) {
				continue;
			}
			Object ret = body.eval(callstack, interpreter);
			if (ret instanceof ReturnControl) {
				switch(( (ReturnControl)ret).kind ) {
					case RETURN:
						return ret;

					case CONTINUE:
						break;

					case BREAK:
						return Primitive.VOID;
				}
			}
		}
        return Primitive.VOID;
    }

}
