lighttpd forum lighty > ssi #if not working

<!--#if expr="" -->
true
<!--#else -->
false
<!--#endif -->


no matter what I try as the expr, all I ever get is true

I also tried it using includes instead of text to the same end

<!--#if expr="" -->
<!--#include virtual="true" -->
<!--#else -->
<!--#include virtual="false" -->
<!--#endif -->

all true :
expr="1 > 2"
expr="!(hello)"
expr="1 > 2 AND 2 < 1"