Unary plus and minus

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.