| SAXONICA | 
The unary minus operator changes the sign of a number. For example -1 is minus one, and
            -0e0 is the double value negative zero.
         
Unary plus has very little effect: the value of +1 is the same as the value of 1.
            It does, however, provide a quick way of forcing untyped values to be numeric, for example you can write
            <xsl:sort select="+@price"/> to force a numeric sort, if you find 
            <xsl:sort select="number(@price)"/> too verbose for your tastes.