Bug 201030 NPE throws out when preview the attached report design
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/script/ScriptEvalUtil.java
"evaluateJSExpr",
				"evaluateJSExpr() scriptText=" + scriptText 
				+ ", source=" + source 
				+ ", lineNo=" + lineNo);
		
		Object result;
		try
		{
			result = JavascriptEvalUtil.evaluateScript( cx, scope, scriptText, source, lineNo );
		}
		catch (BirtException e)
		{
			throw DataException.wrap(e);
		}
		
		
		if ( result instanceof DataExceptionMocker )
		{
			throw DataException.wrap( ((DataExceptionMocker) result ).getCause( ));
		}
		
		return result;
	}
	
	
	/**
	 * Wrap the text and value of the operand
	 * 
	 */
	public static class ExprTextAndValue