Bug 209309 Show javascript errorposition
If a javascript expression has errors, the error message is shown in the last lines in the preview tab. But there is no info where the error occurs. In most cases you had to guess the error location. It would be very helpfull to display the error location.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/executor/ExecutionContext.java
* Evaluate a BIRT expression
	 * 
	 * @param expr
	 *            the expression to be evaluated
	 * @param name
	 *            the file name
	 * @param lineNo
	 *            the line number
	 * 
	 * @return the result if no error exists, otherwise null.
	 */
	public Object evaluate( String expr, String name, int lineNo )
	{
		if ( expr != null )
		{
			try
			{
				return scriptContext.eval( expr, name, lineNo );
			}
			catch ( Throwable e )
			{
				log.log( Level.SEVERE, e.getMessage( ), e );
				addException( new EngineException(
						MessageConstants.SCRIPT_EVALUATION_ERROR, expr, e ) ); 
			}
		}
		return null;
	}	
	/**
	 * evaluate conditional expression. A conditional expression can have an