[xsl] comparing true and false with 0 or 1

["Fraser Goffin" <goffinf@xxxxxxxxxxx>]

I am trying to compare two element values that are of type boolean. In 
either case the XML instance may contain either true or false or 0 or 1. 
I've been looking at the boolean(), number(), and string() functions but I 
can't seem to create an expression that evaluates correctly. e.g. :-

(true = 1) = true
(true = 0) = false
(false = 1) = true
(false = 0) = false

Thanks

Fraser.