Combining dataCollection fields in tableviewrow title

Hello

I'm working with alloy and for creating a tableview I am using the databind method from the main example. When adding a row, I set the title of the row as follows

<TableView id="tbvBooks" dataCollection="books" >
    <TableViewRow title="{bookTitle}" onClick="showBooksDetails"></TableViewRow>
</TableView>

So far so good. However, now I would like to make the row.title a bit more descriptive bij adding an authorname. I tried things like:

<TableView id="tbvBooks" dataCollection="books" >
    <TableViewRow title="{bookTitle} + {bookAuthor}" onClick="showBooksDetails"></TableViewRow>
</TableView>

but no success. Is this possible in the XML? Ideally I would like my tablerow.title to look like:

row.title = bookCode + " - " + bookAuthor;

Thanks Gino