Re: [xsl] () eq () vs () = ()

[Michael Kay <mike@xxxxxxxxxxxx>]

>If () = () is false, then it's intuitive (to me) that deep-equal((), 
()) is also false. The one liner saying that it should be true just 
seems like it could easily say false.

A = B means (some $a in A, $b in B satisfies $a eq $b). Therefore () = 
() is false.

deep-equal(A, B) means (count(A) eq count(B) and every $i in 1 to 
count(A) satisfies A[$i] eq B[$i]). Therefore deep-equal((), ()) is true.

So it's perfectly consistent. It's also absolutely necessary. Given that 
for two elements to be equal, their sequences of children have to be 
deep-equal, it would be very odd if two elements were not deep-equal 
simply because neither has any children. Indeed, it would be very odd if 
an element were not deep-equal to itself.

(Note, the above expansions are approximate. They don't quite handle 
NaN, but that's another can of worms.)

Michael Kay
Saxonica