/*
* 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.
*/

package org.apache.poi.hssf.record.formula.eval;


/**
 * @author Amol S. Deshmukh < amolweb at ya hoo dot com >
 *  
 */
public final class UnaryPlusEval implements OperationEval {

	public static final OperationEval instance = new UnaryPlusEval();
	
	private UnaryPlusEval() {
	}

	public Eval evaluate(Eval[] args, int srcCellRow, short srcCellCol) {
		if(args.length != 1) {
			return ErrorEval.VALUE_INVALID;
		}
		double d;
		try {
			ValueEval ve = OperandResolver.getSingleValue(args[0], srcCellRow, srcCellCol);
			if(ve instanceof StringEval) {
				// Note - asymmetric with UnaryMinus
				// -"hello" evaluates to #VALUE!
				// but +"hello" evaluates to "hello"
				return ve;
			}
			d = OperandResolver.coerceValueToDouble(ve);
		} catch (EvaluationException e) {
			return e.getErrorEval();
		}
		return new NumberEval(+d);
	}

	public int getNumberOfOperands() {
		return 1;
	}

	public int getType() {
		throw new RuntimeException("obsolete code should not be called");
	}
}